CVE-2026-5958

A Time-of-Check Time-of-Use TOCTOU race condition was found in GNU sed. When the -i in-place and --follow-symlinks options are used together, sed resolves the symlink but reopens the path for writing. An attacker with write access to the directory containing the symlink can swap it between the...

CVE-2026-5958 Race Condition in GNU Sed

When sed is invoked with both -i in-place edit and --follow-symlinks, the function opennextfile performs two separate, non-atomic filesystem operations on the same path: 1. resolves symlink to its target and stores the resolved path for determining when output is written, 2. opens the original...