OpenSSL NULL Pointer Dereference Vulnerability - CVE-2025-11187

Issue summary: PBMAC1 parameters in PKCS12 files are missing validation which can trigger a stack-based buffer overflow invalid pointer or NULL pointer dereference during MAC verification. Impact summary: The stack buffer overflow or NULL pointer dereference may cause a crash leading to Denial of Service for an application that parses untrusted PKCS12 files. The buffer overflow may also potentially enable code execution depending on platform mitigations. When verifying a PKCS12 file that uses PBMAC1 for the MAC the PBKDF2 salt and keylength parameters from the file are used without validation. If the value of keylength exceeds the size of the fixed stack buffer used for the derived key (64 bytes) the key derivation will overflow the buffer. The overflow length is attacker-controlled. Also if the salt parameter is not an OCTET STRING type this can lead to invalid or NULL pointer dereference. Exploiting this issue requires a user or application to process a maliciously crafted PKCS12 file. It is uncommon to accept untrusted PKCS12 files in applications as they are usually used to store private keys which are trusted by definition. For this reason the issue was assessed as Moderate severity. The FIPS modules in 3.6 3.5 and 3.4 are not affected by this issue as PKCS12 processing is outside the OpenSSL FIPS module boundary. OpenSSL 3.6 3.5 and 3.4 are vulnerable to this issue. OpenSSL 3.3 3.0 1.1.1 and 1.0.2 are not affected by this issue as they do not support PBMAC1 in PKCS12.