Vulnerability Intelligence Report
Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter()
CVE-2026-50261
A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.
No Active Exploit Signals
CVSS Base Score
7.8
HIGH
Exploitability:1.9
Impact Score:5.9
EPSS Probability:0.20%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-416 ↗Use After Free
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | 0:24.1.9-4.el10_2.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | 0:24.1.5-6.el10_0.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | 0:1.1.0-25.el6_10.18 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.20.4-35.el7_9 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.8.0-36.el7_9.5 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8 | 0:21.1.3-20.el8_10.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8 | 0:1.20.11-28.el8_10.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8 | 0:1.15.0-10.el8_10 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 0:1.20.10-5.el8_4 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 0:1.11.0-8.el8_4.16 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 0:1.20.10-5.el8_4 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 0:1.11.0-8.el8_4.16 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:1.20.11-8.el8_6 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:21.1.3-2.el8_6.7 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 0:1.12.0-6.el8_6.18 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:1.20.11-8.el8_6 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:21.1.3-2.el8_6.7 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 0:1.12.0-6.el8_6.18 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:1.20.11-19.el8_8 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:21.1.3-13.el8_8.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 0:1.12.0-15.el8_8.18 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:1.20.11-19.el8_8 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:21.1.3-13.el8_8.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 0:1.12.0-15.el8_8.18 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9 | 0:24.1.9-4.el9_8.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9 | 0:1.20.11-34.el9_8.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9 | 0:1.15.0-7.el9_8.2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:1.20.11-21.el9_2 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:21.1.3-10.el9_2.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:1.12.0-14.el9_2.15 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | 0:1.20.11-29.el9_4 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | 0:22.1.9-8.el9_4.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | 0:1.13.1-8.el9_4.10 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | 0:1.20.11-34.el9_6 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | 0:23.2.7-6.el9_6.1 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | 0:1.14.1-11.el9_6 < * (unaffected) |
| Red Hat | Red Hat Enterprise Linux 6 | all |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
0.197%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Red Hat, Inc. · Vendor · USA |
| Reserved | 2026-06-04T14:55:24 |
| Published | 2026-06-05T10:36:33 |
| Patch Date | 2026-06-02 |
| Last Updated | 2026-09-28T11:46:21 |
Community Chatter & Buzz