CVE-2026-18374

Passing an effectively empty string to the ,ccs= syntax extension of the mode argument in the fopen function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled.

This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for ccs should not pass them through without validation.