Xorg: xwayland: x.org x server: information disclosure or denial of service via out-of-bounds read in xkb modifier map handling
Summary
| CVE | CVE-2026-34002 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-05 16:16:11 UTC |
| Updated | 2026-05-07 14:39:15 UTC |
| Description | A flaw was found in the X.Org X server. This vulnerability, an out-of-bounds read, affects the XKB (X Keyboard Extension) modifier map handling. An attacker with access to the X11 server can exploit this by sending a malformed request, which causes the server to read beyond its intended memory boundaries. This can lead to the exposure of sensitive information or cause the server to crash, resulting in a denial of service. |
Risk And Classification
Primary CVSS: v3.1 9.1 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS: 0.000290000 probability, percentile 0.082800000 (date 2026-05-11)
Problem Types: CWE-805 | CWE-805 Buffer Access with Incorrect Length Value
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| 3.1 | [email protected] | Secondary | 6.1 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L |
| 3.1 | CNA | CVSS | 6.1 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Redhat | Enterprise Linux | 10.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 6.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 7.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 8.0 | All | All | All |
| Operating System | Redhat | Enterprise Linux | 9.0 | All | All | All |
| Application | X.org | X Server | - | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | Issue Tracking, Third Party Advisory |
| access.redhat.com/security/cve/CVE-2026-34002 | [email protected] | access.redhat.com | Third Party Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Jan-Niklas Sohn (TrendAI Zero Day Initiative) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-25T07:09:50.953Z | Reported to Red Hat. |
| CNA | 2026-05-05T14:01:46.686Z | Made public. |
Workarounds
CNA: To mitigate this vulnerability, restrict access to the X11 server. If the X.Org X server is not required on a system, consider disabling or uninstalling it. For systems where the X server is necessary, ensure that access is limited to trusted users and networks. This can involve configuring `xhost` or implementing firewall rules to restrict connections to the X server. Any changes to X server configuration or service status may require a restart of the X server for the mitigation to take effect, which will impact active graphical sessions.