CVE-2026-62432

evtchn: Race between FIFO expand and reset

State: Published
Severity: 7.3 High
Published: Jul 28, 2026
Updated: Jul 28, 2026
Reserved: Jul 14, 2026

Description

The EVTCHNOP_expand_array hypercall checks for whether FIFO event channels are enabled, but without holding the correct lock. It can race with EVTCHNOP_reset, resulting in dereferencing a NULL pointer.

Scores

CVSS	Score	Vector	Source
3.1	7.3 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	CISA-ADP

Weaknesses

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

Product	Versions
XenXen	consult Xen advisory XSA-505Unknown

References

https://xenbits.xenproject.org/xsa/advisory-505.html
http://xenbits.xen.org/xsa/advisory-505.html
http://www.openwall.com/lists/oss-security/2026/07/28/21

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