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TI-2026-81987 Aliases CVE-2026-93517GHSA-fp5r-grwm-x622

Heap buffer overflow in X.Org Server GLX RenderLarge request

Priority LOW 38CWE-122Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 6 fixed, 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.

Summary

The X.org X server before 21.1.25 and XWayland before 24.1.14 are affected. A heap buffer overflow in the GLX RenderLarge request occurs when dataBytes exceeds cmdlen (CWE-122). A local authenticated X client with low privileges can trigger it, causing crashes or code execution in the X server context.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

A heap buffer overflow in handling GLX RenderLarge request where dataBytes exceeds cmdlen in X.org X server before 21.1.25 and XWayland before 24.1.14 that could be be triggered by an authenticated X client could cause crashes or code execution in X server context.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00193 8th percentileScored 2026-11-07
Fix Partial xorg-x11-server (x.orgg): 21.1.25xwayland (x.org): 24.1.14Red Hat: 5 advisoriesRed Hat: 6 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
x.orggxorg-x11-serverbefore 21.1.2521.1.25Patch availableCNA
x.orgxwaylandbefore 24.1.1424.1.14Patch availableCNA
  • xorg-x11-server Vendorx.orgg Affected before 21.1.25 Fixed in 21.1.25 Patch available CNA
  • xwayland Vendorx.org Affected before 24.1.14 Fixed in 24.1.14 Patch available CNA

Remediation

Update xorg-x11-server to 21.1.25 or later and XWayland to 24.1.14 or later. Red Hat fixes it in RHSA-2026:89747, RHSA-2026:86907, RHSA-2026:85193, RHSA-2026:85191 and RHSA-2026:84574. Red Hat lists Red Hat Enterprise Linux 6 with no fix planned, and Red Hat Enterprise Linux 7, 8 and 9 with no fix available.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA xorg-x11-server (x.orgg) Fixed in 21.1.25
  • Fix · CNA xwayland (x.org) Fixed in 24.1.14

Red Hat 5 advisories

  • RHSA-2026:89747 Released 2026-10-26 · Red Hat rating Important
    xorg-x11-server security update
    • Red Hat Enterprise Linux AppStream (v. 8) xorg-x11-server-1.20.11-28.el8_10.5, xorg-x11-server-Xdmx-1.20.11-28.el8_10.5, xorg-x11-server-Xephyr-1.20.11-28.el8_10.5 +4
    • Red Hat Enterprise Linux CRB (v. 8) xorg-x11-server-devel-1.20.11-28.el8_10.5, xorg-x11-server-source-1.20.11-28.el8_10.5
  • RHSA-2026:86907 Released 2026-10-21 · Red Hat rating Important
    xorg-x11-server-Xwayland security update
    • Red Hat Enterprise Linux AppStream (v. 8) xorg-x11-server-Xwayland-21.1.3-20.el8_10.4
  • RHSA-2026:85193 Released 2026-10-19 · Red Hat rating Important
    xorg-x11-server-Xwayland security update
    • Red Hat Enterprise Linux AppStream (v. 9) xorg-x11-server-Xwayland-24.1.9-4.el9_8.4
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) xorg-x11-server-Xwayland-24.1.9-4.el9_8.4, xorg-x11-server-Xwayland-devel-24.1.9-4.el9_8.4
Show 2 more Red Hat advisories
  • RHSA-2026:85191 Released 2026-10-19 · Red Hat rating Important
    xorg-x11-server-Xwayland security update
    • Red Hat Enterprise Linux AppStream (v. 10) xorg-x11-server-Xwayland-24.1.9-4.el10_2.4
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) xorg-x11-server-Xwayland-devel-24.1.9-4.el10_2.4
  • RHSA-2026:84574 Released 2026-10-19 · Red Hat rating Important
    xorg-x11-server security update
    • Red Hat Enterprise Linux AppStream (v. 9) xorg-x11-server-1.20.11-34.el9_8.5, xorg-x11-server-Xdmx-1.20.11-34.el9_8.5, xorg-x11-server-Xephyr-1.20.11-34.el9_8.5 +4
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) xorg-x11-server-devel-1.20.11-34.el9_8.5, xorg-x11-server-source-1.20.11-34.el9_8.5

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    x.org xwayland 24.1.14

    10 records Highest priority Priority LOW 10 LOW

    Other records, highest priority first

    • TI-2026-82016 Heap buffer overflow in X.Org X Server XInput2 request handlingPriority LOW 35
    • TI-2026-82013 X.Org Server Glamor CopyArea Heap Buffer OverflowPriority LOW 35
    • TI-2026-82007 Heap buffer overflow in X.Org X server XKB keycode range handlingPriority LOW 35
    Show all 10 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:85191
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:86907, RHSA-2026:89747
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:84574, RHSA-2026:85193
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:89747
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:85191
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:84574, RHSA-2026:85193

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-93517
  2. 2026-10-28 Alias added: GHSA-fp5r-grwm-x622
  3. 2026-10-30 Priority changed: MEDIUM → LOW
  4. 2026-11-05 CISA SSVC decision points changed

References

Patch 1

  • TI-2026-81998 Heap buffer overflow in X.Org Server XFIXES pointer barriers CVSS 3.1HIGH 7.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences