X.org X11 Server FreeCounter use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.8$0-$5k3.78-

Summaryinfo

A vulnerability identified as critical has been detected in X.org X11 Server. Affected is the function FreeCounter. Performing a manipulation results in use after free. This vulnerability is known as CVE-2026-50260. Attacking locally is a requirement. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, was found in X.org X11 Server (affected version not known). This affects the function FreeCounter. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.

It is possible to read the advisory at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-50260 since 06/04/2026. The exploitability is told to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/06/2026).

The vulnerability scanner Nessus provides a plugin with the ID 318742 (Linux Distros Unpatched Vulnerability : CVE-2026-50260), 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 (318742), EUVD (EUVD-2026-34816) and CERT Bund (WID-SEC-2026-1774). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Open Source X.Org X11
  • Open Source Xwayland

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.8

VulDB Base Score: 7.8
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (redhat): 🔒

CVSSv2info

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

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 318742
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-50260

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/04/2026 CVE reserved
06/05/2026 +1 days Advisory disclosed
06/05/2026 +0 days VulDB entry created
06/06/2026 +1 days VulDB entry last update

Sourcesinfo

Vendor: x.org

Advisory: access.redhat.com
Status: Not defined

CVE: CVE-2026-50260 (🔒)
GCVE (CVE): GCVE-0-2026-50260
GCVE (VulDB): GCVE-100-368895
EUVD: 🔒
CERT Bund: WID-SEC-2026-1774 - X.Org X11 und Xwayland: Mehrere Schwachstellen

Entryinfo

Created: 06/05/2026 13:57
Updated: 06/06/2026 02:55
Changes: 06/05/2026 13:57 (62), 06/05/2026 16:28 (1), 06/05/2026 17:52 (2), 06/06/2026 02:55 (7)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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