Libgcrypt EUVD-2026-25193

Libgcrypt is the cryptographic library underlying GnuPG and other applications requiring cryptographic primitives. This vulnerability resides in the Dilithium signature algorithm implementation (NIST FIPS 204 post-quantum cryptography standard). The root cause is classified as CWE-787 (Out-of-bounds Write) - specifically, a static array used during Dilithium signing receives writes without validating that indices remain within allocated bounds. Although the vulnerability description notes that attacker-controlled data is not directly used in the array indexing, the lack of bounds enforcement means that legitimate code paths with certain input parameters can write beyond the array's boundaries, corrupting adjacent memory.