CVE-2026-50257

CVE-2026-50257 · Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in misyncdestroyfence()

This page contains facts from public vulnerability sources. Check the original advisory before updating.

This page shows selected source facts. See the linked advisories for the complete description and affected versions.

A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence(). A client that sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would connect to the X server to set up a fence and await that fence, then a second X connection destroys the fence, causing the use-after-free. This may be used to crash the server, or for privilege escalation if the X server runs as root.

CVSS 7.8 · High · EPSS 0.1% · Fix available

Published: 2026-06-05T10:31:22.052Z
Updated: 2026-09-28T11:46:04.104Z

Stack: system

Affected products and versions

red hat enterprise linux 10
Versions
- ≥ 0:24.1.9-4.el10_2.2: Not affected (rpm)
No fix published
red hat enterprise linux 10.0 extended update support
Versions
- ≥ 0:24.1.5-6.el10_0.1: Not affected (rpm)
No fix published
red hat enterprise linux 6 extended lifecycle support - extension
Versions
- ≥ 0:1.1.0-25.el6_10.18: Not affected (rpm)
No fix published
red hat enterprise linux 7 extended lifecycle support
Versions
- ≥ 0:1.20.4-35.el7_9: Not affected (rpm)
No fix published
red hat enterprise linux 7 extended lifecycle support
Versions
- ≥ 0:1.8.0-36.el7_9.5: Not affected (rpm)
No fix published
red hat enterprise linux 8
Versions
- ≥ 0:21.1.3-20.el8_10.2: Not affected (rpm)
No fix published
red hat enterprise linux 8
Versions
- ≥ 0:1.20.11-28.el8_10.2: Not affected (rpm)
No fix published
red hat enterprise linux 8
Versions
- ≥ 0:1.15.0-10.el8_10: Not affected (rpm)
No fix published
red hat enterprise linux 8.4 advanced mission critical update support
Versions
- ≥ 0:1.20.10-5.el8_4: Not affected (rpm)
No fix published
red hat enterprise linux 8.4 advanced mission critical update support
Versions
- ≥ 0:1.11.0-8.el8_4.16: Not affected (rpm)
No fix published
red hat enterprise linux 8.4 extended update support long-life add-on
Versions
- ≥ 0:1.20.10-5.el8_4: Not affected (rpm)
No fix published
red hat enterprise linux 8.4 extended update support long-life add-on
Versions
- ≥ 0:1.11.0-8.el8_4.16: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 advanced mission critical update support
Versions
- ≥ 0:1.20.11-8.el8_6: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 advanced mission critical update support
Versions
- ≥ 0:21.1.3-2.el8_6.7: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 advanced mission critical update support
Versions
- ≥ 0:1.12.0-6.el8_6.18: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 extended update support long-life add-on
Versions
- ≥ 0:1.20.11-8.el8_6: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 extended update support long-life add-on
Versions
- ≥ 0:21.1.3-2.el8_6.7: Not affected (rpm)
No fix published
red hat enterprise linux 8.6 extended update support long-life add-on
Versions
- ≥ 0:1.12.0-6.el8_6.18: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 telecommunications update service
Versions
- ≥ 0:1.20.11-19.el8_8: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 telecommunications update service
Versions
- ≥ 0:21.1.3-13.el8_8.1: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 telecommunications update service
Versions
- ≥ 0:1.12.0-15.el8_8.18: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 update services for sap solutions
Versions
- ≥ 0:1.20.11-19.el8_8: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 update services for sap solutions
Versions
- ≥ 0:21.1.3-13.el8_8.1: Not affected (rpm)
No fix published
red hat enterprise linux 8.8 update services for sap solutions
Versions
- ≥ 0:1.12.0-15.el8_8.18: Not affected (rpm)
No fix published

Original sources

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