Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.20% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-88806High confidence
libX11 XkbGetMap Reply Heap-based Buffer Overflow
x.org · libX11
7.5HighCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 26 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs x.org libX11 and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 26 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 22 affected or under-investigation product states without a fixed product state in the same current advisory
- Debian Security Tracker: 4 affected package states with no published fix
Distribution package intelligence
5 package statesRelease-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.
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 4 affected package states 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 release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | libx11 | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 8 Oct 2026 |
| Debian bookwormbookworm · source | libx11 | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 8 Oct 2026 |
| Debian forkyforky · source | libx11 | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 8 Oct 2026 |
| Debian sidsid · source | libx11 | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 8 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | libx11 | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 7 Oct 2026 |
Direct vendor intelligence
2 currentAuthoritative 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.
CVE-2026-88806 · CSAF 2.0 · revision 6 · interimSUSE Product Security TeamCVE-2026-88806
The vendor explicitly identifies these products as affected by this CVE.
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- Summary
- A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
- Remediation
- To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2026-88806 · CSAF 2.0 · revision 3 · finalRed Hat Product SecuritylibX11: libX11: Heap-based buffer overflow via malicious X server
The vendor explicitly identifies these products as affected by this CVE.
- libX11-common as a component of Red Hat Enterprise Linux 10
- libX11-devel as a component of Red Hat Enterprise Linux 10
- libX11-xcb as a component of Red Hat Enterprise Linux 10
- libX11.src as a component of Red Hat Enterprise Linux 10
- libX11 as a component of Red Hat Enterprise Linux 6
- libX11-common as a component of Red Hat Enterprise Linux 6
- libX11-devel as a component of Red Hat Enterprise Linux 6
- libX11.src as a component of Red Hat Enterprise Linux 6
- libX11 as a component of Red Hat Enterprise Linux 7
- libX11-common as a component of Red Hat Enterprise Linux 7
- libX11-devel as a component of Red Hat Enterprise Linux 7
- libX11.src as a component of Red Hat Enterprise Linux 7
- Summary
- A flaw was found in libX11. A heap-based buffer overflow vulnerability exists during the handling of XkbGetMap replies. A remote attacker, by operating a malicious X server, could exploit this flaw to potentially execute arbitrary code or cause a denial of service on the client system. User interaction is required for exploitation.
- Remediation
- To mitigate this issue, users should avoid connecting to untrusted X servers. When using SSH, ensure that X11 forwarding (`ssh -X` or `ssh -Y`) is only enabled for trusted remote hosts. To prevent X11 forwarding for specific hosts, add `ForwardX11 no` to the relevant host entry in `~/.ssh/config` or `/etc/ssh/ssh_config`. Alternatively, disable X11 forwarding globally by setting `ForwardX11 no` in `/etc/ssh/ssh_config`.
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 26 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
What
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
Why
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
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
A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.
Why
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
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 No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → Heap-based Buffer Overflow → 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-122 ↗
CWE-122: Heap-based Buffer Overflow. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
- 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:HCommon 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.
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
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3
- libX11 as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-6 as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-6-32bit as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-data as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-devel as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-xcb1 as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11-xcb1-32bit as component of SUSE Linux Enterprise Server 15 SP1-LTSS
- libX11 as component of SUSE Linux Enterprise Server 15 SP1
- libX11-6 as component of SUSE Linux Enterprise Server 15 SP1
- and 91 more
- 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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 21 Sept 2026 · Last source change 22 Sept 2026, 03:55 UTC · CWE-122 · Heap-based Buffer Overflow
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-09-22
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-83914
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.SUSE Product Security Team ↗
- Before
- libX11 as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-6 as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-6-32bit as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-data as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-devel as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-xcb1 as component of SUSE Linux Enterprise Desktop 15 SP7; libX11-xcb1-32bit as component of SUSE Linux Enterprise Desktop 15 SP7; libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3; SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS:libX11-6; SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS:libX11-6-32bit; and 241 more
- After
- libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP1; libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP2; libX11 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-6 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-6-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-data as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-xcb1 as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11-xcb1-32bit as component of SUSE Linux Enterprise High Performance Computing 15 SP3; libX11 as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-6 as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-6-32bit as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-data as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-devel as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-xcb1 as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11-xcb1-32bit as component of SUSE Linux Enterprise Server 15 SP1-LTSS; libX11 as component of SUSE Linux Enterprise Server 15 SP1; libX11-6 as component of SUSE Linux Enterprise Server 15 SP1; and 91 more
- Remediation statusRemediation status changed from Awaiting fix to Mitigation available.SUSE Product Security Team ↗
- Before
- Awaiting fix
- After
- Mitigation available
- ENISA EUVD mappingEUVD-2026-83914 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-83914"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
CVE published
Remediation guidance recorded
Remediation guidance recorded
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.