CVE-2026-50261 | A use-after-free flaw was found in the X.Org X server and Xw… | CVSS 7.8 HIGH

Description

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

Metadata

CVE ID: CVE-2026-50261
State: PUBLISHED
Assigner: redhat
Reserved: 2026-06-04 14:55 UTC
Published: 2026-06-05 10:36 UTC
Last updated: 2026-06-06 03:56 UTC
Primary CWE: CWE-416
Use After Free
Vendor / Product: Red Hat / Red Hat Enterprise Linux 10
Sources: cve.org · NVD

Severity & Metrics

7.8 HIGH CVSS 3.1

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (7)

Vendor	Product	Platform	Versions
Red Hat	Red Hat Enterprise Linux 10	—	—
Red Hat	Red Hat Enterprise Linux 6	—	—
Red Hat	Red Hat Enterprise Linux 7	—	—
Red Hat	Red Hat Enterprise Linux 8	—	—
Red Hat	Red Hat Enterprise Linux 8	—	—
Red Hat	Red Hat Enterprise Linux 9	—	—
Red Hat	Red Hat Enterprise Linux 9	—	—

Weakness (CWE)

CWE	Source	Description
CWE-416	cna	Use After Free

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.8	HIGH	3.1	cna	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References (5)