CVE-2026-50261

CVE-2026-50261 is a high-severity vulnerability in Redhat Enterprise Linux with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-50261?
CVE-2026-50261 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-50261 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-50261?
CVE-2026-50261 primarily affects Redhat Enterprise Linux. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-50261?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-50261 have an EU (EUVD) identifier?
Yes. CVE-2026-50261 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34817.
When was CVE-2026-50261 published?
CVE-2026-50261 was published on 2026-06-05 and last updated on 2026-07-08.

References

Affected products (6)

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