X.org X11 Server CheckSetGeom/XkbAddGeomKeyAlias out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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6.8$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in X.org X11 Server. Affected by this issue is the function CheckSetGeom/XkbAddGeomKeyAlias. Performing a manipulation results in out-of-bounds. This vulnerability is reported as CVE-2026-34000. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability classified as critical has been found in X.org X11 Server (the affected version is unknown). This affects the function CheckSetGeom/XkbAddGeomKeyAlias. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in the X.Org X server. This out-of-bounds read vulnerability in the XKB geometry processing, specifically within the `CheckSetGeom()` and `XkbAddGeomKeyAlias` functions, allows an attacker to read uninitialized or out-of-bounds memory. An attacker with a connection to the X11 server, either locally or remotely, can exploit this without user interaction. This could lead to the disclosure of memory contents or cause a denial of service by crashing the server.

The advisory is shared at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-34000 since 03/25/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 312315 (Oracle Linux 8 : tigervnc (ELSA-2026-13414)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (312315) and EUVD (EUVD-2026-27341). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.8

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 9.1
NVD Vector: 🔒

CNA Base Score: 6.1
CNA Vector (redhat): 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 312315
Nessus Name: Oracle Linux 8 : tigervnc (ELSA-2026-13414)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/25/2026 CVE reserved
05/05/2026 +40 days Advisory disclosed
05/05/2026 +0 days VulDB entry created
05/26/2026 +21 days VulDB entry last update

Sourcesinfo

Vendor: x.org

Advisory: access.redhat.com
Status: Not defined

CNA: redhat
CVE: CVE-2026-34000 (🔒)

GCVE (CVE): GCVE-0-2026-34000
GCVE (VulDB): GCVE-100-361197
EUVD: 🔒

Entryinfo

Created: 05/05/2026 19:08
Updated: 05/26/2026 06:21
Changes: 05/05/2026 19:08 (62), 05/06/2026 11:30 (2), 05/20/2026 07:50 (11), 05/26/2026 06:21 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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