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Full vulnerability report · 2026
CVE-2026-96280High confidence

Flatpak: flatpak: buffer overflow in oci delta stream path names on 32-bit systems

Red Hat · Red Hat Enterprise Linux 10

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.60% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Red Hat Red Hat Enterprise Linux 10 and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourceflatpakVendor fix publishedDebian records a fixed source-package version for this release.1.16.6-1~deb13u2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourceflatpakAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourceflatpakVendor fix publishedDebian records a fixed source-package version for this release.1.18.1-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourceflatpakVendor fix publishedDebian records a fixed source-package version for this release.1.18.1-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appsflatpakUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 6 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current
CVE-2026-96280 · CSAF 2.0 · revision 3 · interimSUSE Product Security TeamCVE-2026-96280
196 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • flatpak as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-devel as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-remote-flathub as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-zsh-completion as component of SUSE Linux Enterprise Desktop 15 SP7
  • libflatpak0 as component of SUSE Linux Enterprise Desktop 15 SP7
  • system-user-flatpak as component of SUSE Linux Enterprise Desktop 15 SP7
  • typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2
Summary
The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.
Remediation
No remediation text is recorded.
CVE-2026-96280 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityflatpak: flatpak: Buffer overflow in OCI delta stream path names on 32-bit systems
23 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • flatpak as a component of Red Hat Enterprise Linux 10
  • flatpak-devel as a component of Red Hat Enterprise Linux 10
  • flatpak-libs as a component of Red Hat Enterprise Linux 10
  • flatpak-selinux as a component of Red Hat Enterprise Linux 10
  • flatpak-session-helper as a component of Red Hat Enterprise Linux 10
  • flatpak.src as a component of Red Hat Enterprise Linux 10
  • flatpak as a component of Red Hat Enterprise Linux 7
  • flatpak-builder as a component of Red Hat Enterprise Linux 7
  • flatpak-devel as a component of Red Hat Enterprise Linux 7
  • flatpak-libs as a component of Red Hat Enterprise Linux 7
  • flatpak.src as a component of Red Hat Enterprise Linux 7
  • flatpak as a component of Red Hat Enterprise Linux 8
Summary
The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.
Remediation
Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-88015

No EUVD known-exploited evidence

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

What

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

Why

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

Why

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Numeric Truncation Error → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-197 ↗

CWE-197: Numeric Truncation Error. Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-197
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-88015Official EUVD mapping

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

Official EUVD record ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
  • flatpak as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-devel as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-remote-flathub as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak-zsh-completion as component of SUSE Linux Enterprise Desktop 15 SP7
  • libflatpak0 as component of SUSE Linux Enterprise Desktop 15 SP7
  • system-user-flatpak as component of SUSE Linux Enterprise Desktop 15 SP7
  • typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise Desktop 15 SP7
  • flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • and 166 more
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles1 stored document

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

  • CVE-2026-96280 Common Vulnerabilities and Exposures | SUSE →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026CVE-2026-96280 Common Vulnerabilities and Exposures [Previous] [Index] [Next] Upstream information CVE-2026-96280 at MITRE Description SUSE information Overall state of this security issue: Pending This issue is currently rated as having important severity. CVSS v3 Scores CVSS detail SUSE Base Score 7.5 Vector CV
04

Evidence and provenance

Published 27 Sept 2026 · Last source change 29 Sept 2026, 15:50 UTC · CWE-197 · Numeric Truncation Error

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-28
European sourceENISA EUVD · EUVD-2026-88015
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-88015 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-88015"}
    ENISA EUVD ↗
  2. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-96280 to remediation: access.redhat.com/CVE-2026-96280.
    Before
    remediation: access.redhat.com/CVE-2026-96280
    After
    remediation: access.redhat.com/CVE-2026-96280
    Red Hat Product Security ↗
  3. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Red Hat Product Security ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    After
    flatpak as a component of Red Hat Enterprise Linux 10; flatpak-devel as a component of Red Hat Enterprise Linux 10; flatpak-libs as a component of Red Hat Enterprise Linux 10; flatpak-selinux as a component of Red Hat Enterprise Linux 10; flatpak-session-helper as a component of Red Hat Enterprise Linux 10; flatpak.src as a component of Red Hat Enterprise Linux 10; flatpak as a component of Red Hat Enterprise Linux 7; flatpak-builder as a component of Red Hat Enterprise Linux 7; flatpak-devel as a component of Red Hat Enterprise Linux 7; flatpak-libs as a component of Red Hat Enterprise Linux 7; flatpak.src as a component of Red Hat Enterprise Linux 7; flatpak as a component of Red Hat Enterprise Linux 8; flatpak-devel as a component of Red Hat Enterprise Linux 8; flatpak-libs as a component of Red Hat Enterprise Linux 8; flatpak-selinux as a component of Red Hat Enterprise Linux 8; flatpak-session-helper as a component of Red Hat Enterprise Linux 8; flatpak.src as a component of Red Hat Enterprise Linux 8; flatpak as a component of Red Hat Enterprise Linux 9; flatpak-devel as a component of Red Hat Enterprise Linux 9; flatpak-libs as a component of Red Hat Enterprise Linux 9; flatpak-selinux as a component of Red Hat Enterprise Linux 9; flatpak-session-helper as a component of Red Hat Enterprise Linux 9; flatpak.src as a component of Red Hat Enterprise Linux 9
    Red Hat Product Security ↗
  5. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: suse.com/CVE-2026-96280; removed vendor advisory: suse.com/CVE-2026-96280.
    Before
    remediation: suse.com/CVE-2026-96280 · vendor advisory: suse.com/CVE-2026-96280
    After
    no authoritative guidance recorded
    CNA ↗
  6. Affected versionsThe structured affected or fixed version information changed.
    Before
    flatpak as component of SUSE Linux Enterprise Desktop 15 SP7; flatpak-devel as component of SUSE Linux Enterprise Desktop 15 SP7; flatpak-remote-flathub as component of SUSE Linux Enterprise Desktop 15 SP7; flatpak-zsh-completion as component of SUSE Linux Enterprise Desktop 15 SP7; libflatpak0 as component of SUSE Linux Enterprise Desktop 15 SP7; system-user-flatpak as component of SUSE Linux Enterprise Desktop 15 SP7; typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise Desktop 15 SP7; flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2; flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2; flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP2; typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP3; flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP3; flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP3; typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; typelib-1_0-Flatpak-1_0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS; flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4; flatpak-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP4; flatpak-zsh-completion as component of SUSE Linux Enterprise High Performance Computing 15 SP4; libflatpak0 as component of SUSE Linux Enterprise High Performance Computing 15 SP4; system-user-flatpak as component of SUSE Linux Enterprise High Performance Computing 15 SP4; and 166 more · Fixed: No fixed product state is explicitly recorded in the vendor advisory.
    After
    See the vendor and CVE records for the affected range. · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  7. SeveritySeverity changed from Unknown to High.
    Before
    Unknown
    After
    High
    CNA ↗
  8. CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).
    Before
    not recorded
    After
    7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
    CNA ↗
  9. Catalogue recordCVE added to the BlackTree catalogue.
    Authoritative vendor CSAF advisory ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-88015↗Vendor CSAF · SUSE Product Security Team↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-96280 · cve.blacktree.nl