A Time-of-Check to Time-of-Use (TOCTOU) race condition exists in the mkfifo utility of uutils coreutils. The utility creates a FIFO and then performs a path-based chmod to set permissions. A local attacker with write access to the parent directory can swap the newly created FIFO for a symbolic link between these two operations. This redirects the chmod call to an arbitrary file, potentially enabling privilege escalation if the utility is run with elevated privileges.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-35352
• uutils/coreutils#10020
• http://www.openwall.com/lists/oss-security/2026/05/04/4
• http://www.openwall.com/lists/oss-security/2026/05/04/5
• http://www.openwall.com/lists/oss-security/2026/05/04/6