REDHAT-BUG-2481891: Null Pointer Dereference

NULL Pointer Dereference in CRMF EncryptedValue Decryption

NULL Pointer Dereference in CRMF EncryptedValue Decryption (CVE-2026-42767) Severity: Low

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

OpenSSL 4.0, 3.6, and 3.5 are vulnerable to this issue.

OpenSSL 1.0.2, 1.1.1, 3.0, and 3.4 are not affected by this issue.

OpenSSL 4.0 users should upgrade to OpenSSL 4.0.1 OpenSSL 3.6 users should upgrade to OpenSSL 3.6.3. OpenSSL 3.5 users should upgrade to OpenSSL 3.5.7.

This issue was reported by Zhanpeng Liu (Tencent Xuanwu Lab), Guannan Wang (Tencent Xuanwu Lab) and Guancheng Li (Tencent Xuanwu Lab) on 27th March 2026. The fix was developed by Igor Ustinov.