CVE-2026-49412
Use-after-free bug in the IPV6_MSFILTER socket option handler
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.
INFO
Published Date :
June 27, 2026, 9:16 a.m.
Last Modified :
July 1, 2026, 2:04 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the kernel to a patched version.
- Apply necessary security updates.
- Rebuild the kernel with the fix.
- Restart the affected system.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49412.
| URL | Resource |
|---|---|
| https://security.freebsd.org/advisories/FreeBSD-SA-26:29.ip6_multicast.asc | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49412 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49412
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49412 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49412 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 01, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p11:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p12:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p13:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p7:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p8:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p14:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p9:*:*:*:*:*:* Added Reference Type FreeBSD: https://security.freebsd.org/advisories/FreeBSD-SA-26:29.ip6_multicast.asc Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 30, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-49412', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-29T13:06:26.101458Z'} {'id': 'CVE-2026-49412', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-29T00:00:00+00:00'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 29, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added SSVC {'id': 'CVE-2026-49412', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-29T13:06:26.101458Z'} -
New CVE Received by [email protected]
Jun. 27, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'FreeBSD', 'modules': ['ip6_multicast'], 'product': 'FreeBSD', 'versions': [{'status': 'affected', 'version': '15.0-RELEASE', 'lessThan': 'p10', 'versionType': 'release'}, {'status': 'affected', 'version': '14.4-RELEASE', 'lessThan': 'p6', 'versionType': 'release'}, {'status': 'affected', 'version': '14.3-RELEASE', 'lessThan': 'p15', 'versionType': 'release'}], 'defaultStatus': 'unknown'}] Added 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. Added CWE CWE-416 Added Reference https://security.freebsd.org/advisories/FreeBSD-SA-26:29.ip6_multicast.asc