High severity · published Jun 27, 2026
CVE-2026-49412
Use-after-free bug in the IPV6_MSFILTER socket option handler
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
The 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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 4% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeBSD · FreeBSD
15.0-RELEASE before p10; 14.4-RELEASE before p6; 14.3-RELEASE before p15 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49412
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49412
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:29.ip6_multicast.asc
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