CVE-2026-35355 uutils coreutils install Arbitrary File Overwrite via Symlink TOCTOU Race

What is CVE-2026-35355?

CVE-2026-35355 is a medium-severity vulnerability in Uutils coreutils, published on 22 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The install utility in uutils coreutils is vulnerable to a Time-of-Check to Time-of-Use (TOCTOU) race condition during file installation. The implementation unlinks an existing destination file and then recreates it using a path-based operation without the O_EXCL flag. A local attacker can exploit the window between the unlink and the subsequent creation to swap the path with a symbolic link, allowing them to redirect privileged writes to overwrite arbitrary system files.

Weakness: CWE-367

Which versions are affected by CVE-2026-35355?

2 open source packages ship an affected version, including uu_install. It affects 1 product.

Products include Uutils Coreutils.

How do I fix CVE-2026-35355?

Upgrade uu_install to 0.6.0 or later.

Is CVE-2026-35355 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35355 exists.

Other vulnerabilities in Uutils coreutils

• CVE-2026-35338 uutils coreutils chmod Path Traversal Bypass of --preserve-root High 7.3
• CVE-2026-35368 uutils coreutils chroot Local Privilege Escalation and chroot Escape in via Name Service Switch (NSS) Injection High 7.2
• CVE-2026-35341 uutils coreutils mkfifo Unauthorized Permission Change on Existing Files High 7.1
• CVE-2026-35352 uutils coreutils mkfifo Privilege Escalation via TOCTOU Race Condition High 7.0
• CVE-2026-35349 uutils coreutils Path-Based Safety Bypass with --preserve-root Medium 6.7

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-35355, GHSA-239g-2685-54x3, UBUNTU-CVE-2026-35355.