Use-after-free bug in the IPV6_MSFILTER socket option handler

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Summary

CVECVE-2026-49412
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-27 09:16:23 UTC
Updated2026-06-27 09:16:23 UTC
DescriptionThe kernel handler for IPV6_MSFILTER dropped a serializing lock in order to copy the source-filter list from userspace, then reacquired the lock. During this window another thread could free the multicast filter structure, leaving the handler with a stale pointer to freed memory. An unprivileged local user can exploit this use-after-free to escalate privileges.

Risk And Classification

Problem Types: CWE-416 | CWE-416 CWE-416: Use After Free

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeBSD FreeBSD affected 15.0-RELEASE p10 release Not specified
CNA FreeBSD FreeBSD affected 14.4-RELEASE p6 release Not specified
CNA FreeBSD FreeBSD affected 14.3-RELEASE p15 release Not specified

References

ReferenceSourceLinkTags
security.freebsd.org/advisories/FreeBSD-SA-26:29.ip6_multicast.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: Andrew Griffiths at Calif.io (en)

CNA: Maik Münch (en)

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