Bug 2392528 (CVE-2025-9820)

Stack-based buffer overflow vulnerability in the PKCS#11 token initialization function gnutls_pkcs11_token_init() of the GnuTLS library. The flaw is caused by an unsafe memcpy into a fixed-size stack buffer (flabel[32]) without proper bounds checking. If an attacker provides a token label longer than 32 bytes, it leads to out-of-bounds memory writes, causing a crash or, in some environments, potential code execution. Although the vulnerability requires local access or interaction with a malicious PKCS#11 token, it poses a security risk by enabling denial-of-service or possible privilege escalation in applications relying on GnuTLS.