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PatchSiren cyber security CVE debrief

CVE-2026-50260 Red Hat CVE debrief

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-05
Original CVE updated
2026-08-05
Advisory published
2026-06-05
Advisory updated
2026-08-05

Who should care

Users of X.Org X server and Xwayland should apply patches or mitigations to address this vulnerability.

Technical summary

The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. The CVSS vector is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. The weakness is CWE-416.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates from vendors
  • Restrict access to the X server
  • Monitor for suspicious activity

Evidence notes

The vulnerability was published on 2026-06-05T12:16:39.430Z and modified on 2026-06-11T18:36:20.720Z.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50260 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50260

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-50260 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50260

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.