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VulnerabilityPublished Updated

CVE-2026-50257: Red Hat Enterprise Linux 10 · Use After Free

Affects Red Hat Enterprise Linux 10Source CVE Database V5

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Not known to be exploited · CVSS 7.8 High.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Red Hat Enterprise Linux 10xorg-x11-server-XwaylandAffected–Fixed in–
Red Hat Enterprise Linux 10.0 Extended Update Supportxorg-x11-server-XwaylandAffected–Fixed in–
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervncAffected–Fixed in–
Red Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-serverAffected–Fixed in–
Red Hat Enterprise Linux 7 Extended Lifecycle SupporttigervncAffected–Fixed in–
Red Hat Enterprise Linux 8xorg-x11-server-XwaylandAffected–Fixed in–

AI-suggested

Red Hat has released official security updates for xorg-x11-server and xorg-x11-server-Xwayland in Red Hat Enterprise Linux 8 to fix this vulnerability. Users should apply the updates as described in Red Hat advisory RHSA-2026:26562. No additional mitigation steps are indicated beyond applying the official patches.

Description

CVE-2026-50257 is a use-after-free vulnerability in the X.Org X server and Xwayland's miSyncDestroyFence() function. An attacker with local access can trigger this flaw by setting up multiple fence triggers and manipulating their lifecycle, potentially causing a server crash or privilege escalation if the X server runs as root. Red Hat has issued a security advisory with patches addressing this and related vulnerabilities in xorg-x11-server and xorg-x11-server-Xwayland for Red Hat Enterprise Linux 8. The advisory rates the impact as Important and provides updated packages to remediate the issue.

References

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