VDB-376795 · CVE-2026-56000 · GCVE-0-2026-56000

X.Org xorg-x11-server/xwayland prior 21.2.24/24.1.13 GLX CommonMakeCurrent use after free

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.4	$0-$5k	0.60+

Summaryinfo

A vulnerability classified as very critical has been found in X.Org xorg-x11-server and xwayland. Affected by this issue is the function CommonMakeCurrent of the component GLX. This manipulation causes use after free. This vulnerability is registered as CVE-2026-56000. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability classified as very critical was found in X.Org xorg-x11-server and xwayland. Affected by this vulnerability is the function CommonMakeCurrent of the component GLX. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Local attackers with a X connection able to provide GLX commit to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a Heap Use After Free, due to CommonMakeCurrent() pointing into potentially reallocated memory.

It is possible to read the advisory at gitlab.freedesktop.org. This vulnerability is known as CVE-2026-56000 since 06/18/2026. The exploitation appears 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 07/08/2026).

Upgrading to version 21.2.24 or 24.1.13 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Windowing System Software

Vendor

X.Org

Name

License

open-source

Website

Vendor: https://www.x.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: xorg-x11-server/xwayland 21.2.24/24.1.13

Timelineinfo

06/18/2026 CVE reserved
07/08/2026 +20 days Advisory disclosed
07/08/2026 +0 days VulDB entry created
07/08/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: x.org

Advisory: gitlab.freedesktop.org
Status: Confirmed

CVE: CVE-2026-56000 (🔒)
GCVE (CVE): GCVE-0-2026-56000
GCVE (VulDB): GCVE-100-376795

Entryinfo

Created: 07/08/2026 10:50
Changes: 07/08/2026 10:50 (54)
Complete: 🔍
Cache ID: 216::103