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CVE-2026-50256VulnerabilityPublished Updated

Red Hat Security Advisory: xorg-x11-server security, bug fix, and enhancement update

Affects Red Hat xorg-x11-server security,Source GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-50256· High 7.8

Not known to be exploited · CVSS 7.8 High.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.

Sources agree

CVSS scores by source
CNA (redhat)CVSS 3.17.8
ADP (redhat-SADP)CVSS 3.17.8
EPSS
0.1% chance of exploitation in 30 days – higher than 4% 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 5 Nov 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–

Description

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon. Security Fix(es): * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch (CVE-2026-50256) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() (CVE-2026-50257) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels (CVE-2026-50258) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing (CVE-2026-50259) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() (CVE-2026-50260) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() (CVE-2026-50261) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes (CVE-2026-50262) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() (CVE-2026-50263) * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264) Bug Fix(es) and Enhancement(s): * [xserver] Backport other security fixes without a CVE assigned [rhel-8.10.z] (JIRA:RHEL-184289) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References

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