Linux kernel AT_SECURE bug allows local setuid exploitation
CVE-2026-49413 Published on June 27, 2026
Flaw in Linuxulator execution of setugid binaries
The Linuxulator determined whether a binary was set-user-ID or set-group-ID by checking the P_SUGID process flag. During execve(2), this flag is not yet set at the point where the auxiliary vector is constructed, so AT_SECURE was incorrectly set to zero for set-user-ID and set-group-ID executables.
An unprivileged local user can inject a shared library via LD_PRELOAD into a set-user-ID or set-group-ID Linux binary, gaining the privileges of that binary.
Vulnerability Analysis
CVE-2026-49413 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity and availability.
Weakness Type
Incorrect Privilege Assignment
A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor.
Products Associated with CVE-2026-49413
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Affected Versions
FreeBSD:- Version 15.0-RELEASE and below p10 is affected.
- Version 14.4-RELEASE and below p6 is affected.
- Version 14.3-RELEASE and below p15 is affected.