CVE-2026-40253: openCryptoki: Memory safety vulnerabilities in BER/DER decoders in asn1.c

openCryptoki is a PKCS#11 library and provides tooling for Linux and AIX. In versions 3.26.0 and below, the BER/DER decoding functions in the shared common library (asn1.c) accept a raw pointer but no buffer length parameter, and trust attacker-controlled BER length fields without validating them against actual buffer boundaries. All primitive decoders are affected: berdecodeINTEGER, berdecodeSEQUENCE, berdecodeOCTETSTRING, berdecodeBITSTRING, and berdecodeCHOICE. Additionally, berdecodeINTEGER can produce integer underflows when the encoded length is zero. An attacker supplying a malformed BER-encoded cryptographic object through PKCS#11 operations such as CCreateObject or CUnwrapKey, token loading from disk, or remote backend communication can trigger out-of-bounds reads. This affects all token backends (Soft, ICA, CCA, TPM, EP11, ICSF) since the vulnerable code is in the shared common library. A patch is available thorugh commit ed378f463ef73364c89feb0fc923f4dc867332a3.

— MITRE