Vulnerability Description
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: ber_decode_INTEGER, ber_decode_SEQUENCE, ber_decode_OCTET_STRING, ber_decode_BIT_STRING, and ber_decode_CHOICE. Additionally, ber_decode_INTEGER 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 C_CreateObject or C_UnwrapKey, 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Opencryptoki Project | Opencryptoki | <= 3.26.0 |
Related Weaknesses (CWE)
References
- https://github.com/opencryptoki/opencryptoki/commit/ed378f463ef73364c89feb0fc923Patch
- https://github.com/opencryptoki/opencryptoki/security/advisories/GHSA-c9cf-6vr4-ExploitMitigationPatch
- https://github.com/opencryptoki/opencryptoki/security/advisories/GHSA-c9cf-6vr4-ExploitMitigationPatch
FAQ
What is CVE-2026-40253?
CVE-2026-40253 is a vulnerability with a CVSS score of 6.8 (MEDIUM). 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...
How severe is CVE-2026-40253?
CVE-2026-40253 has been rated MEDIUM with a CVSS base score of 6.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40253?
Check the references section above for vendor advisories and patch information. Affected products include: Opencryptoki Project Opencryptoki.