FreeBSD Kernel SUID Execve Race Enables Local Privilege Escalation
CVE-2026-49415 Published on August 19, 2026
Local privilege escalation via execve(2) TOCTOU race
During execve(2) of a SUID binary, the new virtual address space is installed before the process credentials are updated. During this window, a process running as the same user can access the target process's memory via procfs or linprocfs, because the kernel's debugging permission check still saw the original credentials.
An unprivileged local user can exploit this race to modify the address space of a SUID binary before its credentials are elevated, potentially gaining full control of the affected system.
Weakness Type
What is a TOCTTOU Vulnerability?
The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.
CVE-2026-49415 has been classified to as a TOCTTOU vulnerability or weakness.
Products Associated with CVE-2026-49415
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Affected Versions
FreeBSD:- Version 15.1-RELEASE and below p1 is affected.
- Version 15.0-RELEASE and below p11 is affected.
- Version 14.4-RELEASE and below p7 is affected.
- Version 14.3-RELEASE and below p16 is affected.