Memory safety bugs in kqueue copy-on-fork implementation

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-58099
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-15 07:18:02 UTC
Updated2026-10-16 04:18:32 UTC
DescriptionWhen copying knotes from a parent kqueue to a child, the copy code did not correctly exclude marker knotes (used internally to track list traversal position) before marking them as in-flux and releasing the kqueue lock. If another thread freed a marker while the lock was dropped, the subsequent in-flux decrement operated on freed memory. An unprivileged local user may be able to exploit these races to escalate privileges.

Risk And Classification

Problem Types: CWE-362 | CWE-416 | CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') | CWE-416 CWE-416: Use After Free

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeBSD FreeBSD affected 15.1-RELEASE p4 release Not specified

References

ReferenceSourceLinkTags
security.freebsd.org/advisories/FreeBSD-SA-26:65.kqueue.asc [email protected] security.freebsd.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Reo Shiseki (en)

CNA: Mark Johnston (en)

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