CVE-2026-49428

posixshm: system calls can incorrectly free memory of largepage objects

State: Published
Severity: 8.4 High
Published: Aug 19, 2026
Updated: Aug 20, 2026
Reserved: May 29, 2026

Description

Certain system calls, such open(2) with the O_TRUNC flag set, and fspacectl(2), could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this.

An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.

Scores

CVSS	Score	Vector	Source
3.1	8.4 High	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes

Affected Products

Product	Versions
FreeBSDFreeBSD	15.1-RELEASE to before p1Affected 15.0-RELEASE to before p11Affected 14.4-RELEASE to before p7Affected 14.3-RELEASE to before p16Affected

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:44.posixshm.ascvendor-advisory

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