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Full vulnerability report · 2026
CVE-2026-15370High confidence

Libssh: libssh: stack buffer overflow in sftp server longname construction

Red Hat · Red Hat Enterprise Linux 10

Official source articles: Red Hat RHSA-2026:47768 ↗ · Red Hat RHSA-2026:55855 ↗. Check the applicable product and release in the original source.

6.7MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Low, lowered one band.downgradedsince 17 Aug 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.17% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • 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. Verify the installed build against the product-specific fixed version after deployment.
  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: No default targetRemediation target: Normal maintenance

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.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

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

4 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

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 · sourcelibsshVendor fix publishedDebian records a fixed source-package version for this release.0.11.5-0+deb13u1Debian Security Tracker ↗Source updated 7 Oct 2026
Debian bookwormbookworm · sourcelibsshAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Debian forkyforky · sourcelibsshVendor fix publishedDebian records a fixed source-package version for this release.0.12.1-1Debian Security Tracker ↗Source updated 7 Oct 2026
Debian sidsid · sourcelibsshVendor fix publishedDebian records a fixed source-package version for this release.0.12.1-1Debian Security Tracker ↗Source updated 7 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.

1 current
CVE-2026-15370 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitylibssh: libssh: stack buffer overflow in SFTP server longname construction
30 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • libssh-debuginfo-0:0.12.0-3.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debuginfo-0:0.12.0-3.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debuginfo-0:0.12.0-3.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debuginfo-0:0.12.0-3.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debugsource-0:0.12.0-3.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debugsource-0:0.12.0-3.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debugsource-0:0.12.0-3.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-debugsource-0:0.12.0-3.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-devel-0:0.12.0-3.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-devel-0:0.12.0-3.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-devel-0:0.12.0-3.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
  • libssh-devel-0:0.12.0-3.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
Summary
A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
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-2026-46169

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.

What

A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.

Why

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

What

A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.

Why

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

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
local access → Stack-based Buffer Overflow → disrupt the affected service
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
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-121 ↗

CWE-121: Stack-based Buffer Overflow. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:H/PR:L/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.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level 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
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
Denial of serviceCWE-121
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-2428libssh: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in libssh ausnutzen, um erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Angriff auszulösen und Daten zu manipulieren.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260722Security Bulletin 22 Jul 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 22 Jul 2026, published on 22 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-026239libssh等の複数ベンダの製品におけるスタックベースのバッファオーバーフローの脆弱性

libsshに脆弱性が発見されました。SFTPサーバのディレクトリ一覧表示中に、longnameフィールドが固定サイズのスタックバッファに対して安全でない連結で構築されます。クライアントが攻撃者が制御するファイル名を一覧表示させた場合、十分に長い名前によってスタックバッファがオーバーフローし、サーバがクラッシュしたり、コードが実行される可能性があります。

Official advisory ↗
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 availability varies by product
Affected
See the vendor and CVE records for the affected range.
Fixed
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 21 Jul 2026 · Last source change 17 Aug 2026, 21:54 UTC · CWE-121 · Stack-based Buffer Overflow

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 2026-08-14
European sourceENISA EUVD · EUVD-2026-46169
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: access.redhat.com/RHSA-2026:55855.
    Before
    remediation: access.redhat.com/RHSA-2026:47768 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 1 more references
    After
    remediation: access.redhat.com/RHSA-2026:47768 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 2 more references
    secalert@redhat.com ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 0:0.12.0-3.el10_2 < *; 0.12.2-1.hum1 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Enterprise Linux 10: 0:0.12.0-3.el10_2 < *; Red Hat Hardened Images: 0.12.2-1.hum1 < *
    CNA ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:47768; removed remediation: access.redhat.com/RHSA-2026:55855; removed vendor advisory: access.redhat.com/RHSA-2026:55855.
    Before
    remediation: access.redhat.com/RHSA-2026:55855 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 2 more references
    After
    remediation: access.redhat.com/RHSA-2026:47768 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 1 more references
    secalert@redhat.com ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:55855; added vendor advisory: access.redhat.com/RHSA-2026:55855; removed remediation: access.redhat.com/RHSA-2026:47768.
    Before
    remediation: access.redhat.com/RHSA-2026:47768 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 1 more references
    After
    remediation: access.redhat.com/RHSA-2026:55855 · vendor advisory: access.redhat.com/CVE-2026-15370 · vendor advisory: access.redhat.com/RHSA-2026:47768 · 2 more references
    secalert@redhat.com ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 0.12.2-1.hum1 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: 0:0.12.0-3.el10_2 < *; 0.12.2-1.hum1 < *
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-46169↗Vendor advisory↗CVE authority or vendor reference · Red Hat RHSA-2026:47768↗Vendor advisory · Red Hat RHSA-2026:55855↗Vendor advisory↗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-2026-15370 · cve.blacktree.nl