Red Hat Security Advisory: xorg-x11-server-Xwayland security, bug fix, and enhancement update
Affects Red Hat xorg-serverSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 5 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10xorg-serverpkg:deb/ubuntu/xorg-server?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10xwaylandpkg:deb/ubuntu/xwayland?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSxorg-serverpkg:deb/ubuntu/xorg-server?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSxwaylandpkg:deb/ubuntu/xwayland?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10xorg-serverpkg:deb/ubuntu/xorg-server?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10xwaylandpkg:deb/ubuntu/xwayland?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Xwayland is an X server for running X clients under Wayland. 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): * [xwayland] Backport other security fixes without a CVE assigned [rhel-8.10.z] (JIRA:RHEL-184293) 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
- access.redhat.com/errata/RHSA-2026:26562 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485380 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485382 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485383 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485384 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485385 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485386 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485387 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485388 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2485389 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_26562.json (opens in a new tab)