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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-49412
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-27 09:16:23 UTC
Updated2026-07-01 14:04:44 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

Primary CVSS: v3.1 7.8 HIGH from ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001040000 probability, percentile 0.012490000 (date 2026-07-04)

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

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Freebsd Freebsd 14.3 - All All
Operating System Freebsd Freebsd 14.3 p1 All All
Operating System Freebsd Freebsd 14.3 p10 All All
Operating System Freebsd Freebsd 14.3 p11 All All
Operating System Freebsd Freebsd 14.3 p12 All All
Operating System Freebsd Freebsd 14.3 p13 All All
Operating System Freebsd Freebsd 14.3 p14 All All
Operating System Freebsd Freebsd 14.3 p2 All All
Operating System Freebsd Freebsd 14.3 p3 All All
Operating System Freebsd Freebsd 14.3 p4 All All
Operating System Freebsd Freebsd 14.3 p5 All All
Operating System Freebsd Freebsd 14.3 p6 All All
Operating System Freebsd Freebsd 14.3 p7 All All
Operating System Freebsd Freebsd 14.3 p8 All All
Operating System Freebsd Freebsd 14.3 p9 All All
Operating System Freebsd Freebsd 14.4 - All All
Operating System Freebsd Freebsd 14.4 p1 All All
Operating System Freebsd Freebsd 14.4 p2 All All
Operating System Freebsd Freebsd 14.4 p3 All All
Operating System Freebsd Freebsd 14.4 p4 All All
Operating System Freebsd Freebsd 14.4 p5 All All
Operating System Freebsd Freebsd 15.0 - All All
Operating System Freebsd Freebsd 15.0 p1 All All
Operating System Freebsd Freebsd 15.0 p2 All All
Operating System Freebsd Freebsd 15.0 p3 All All
Operating System Freebsd Freebsd 15.0 p4 All All
Operating System Freebsd Freebsd 15.0 p5 All All
Operating System Freebsd Freebsd 15.0 p6 All All
Operating System Freebsd Freebsd 15.0 p7 All All
Operating System Freebsd Freebsd 15.0 p8 All All
Operating System Freebsd Freebsd 15.0 p9 All All

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 Vendor Advisory
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)

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report