OpenSSL Security Advisory: Fixes for CVE-2026-31790 Memory Leak, OOB Read, and UAF

OpenSSL Security Advisory Summary (April 17, 2026) 1. Error Handling in RSA KEM RSAES-OAEP Encapsulation (CVE-2026-31790) Severity: Moderate Vulnerability Overview: Applications using RSAES-OAEP key encapsulation to establish a secret encryption key may send uninitialized memory buffer contents to a malicious peer. RSA public key encryption returns -1 on error, but the affected code only tests if the return value is non-zero. If RSA encryption fails, encapsulation may still produce output. If an application uses with RSA/RSASV without first validating the provided invalid RSA public key, it may lead to leakage of state or uninitialized content. Affected Versions: FIPS Module 3.6, 3.5, 3.4, 3.3, 3.1, and 3.0 are affected. OpenSSL 3.6, 3.5, 3.4, 3.3, and 3.0 are affected. OpenSSL 1.0.2 and 1.1.1 are not affected. Remediation: OpenSSL 3.0 users should upgrade to 3.0.20. OpenSSL 3.3 users should upgrade to 3.3.7. OpenSSL 3.4 users should upgrade to 3.4.5. OpenSSL 3.5 users should upgrade to 3.5.6. OpenSSL 3.6 users should upgrade to 3.6.2. Workaround: Call or before invoking . 2. Out-of-Bounds Read in AES-CFB128 with AVX-SI2 Support on x86-64 (CVE-2026-28386) Severity: Low Vulnerability Overview: Applications using AES-CFB128 encryption or decryption on systems with AVX-SI2 and VAES support may trigger an out-of-bounds read of input data bytes (up to 15 bytes) when processing partial encrypted blocks, leading to a crash or denial of service. Affected Versions: Only x86-64 systems with AVX-SI2 and VAES instruction set support are affected. OpenSSL FIPS Module 3.6 versions are affected. OpenSSL 3.8, 3.3, 3.4, 3.5, 1.1.1, and 1.0.2 are not affected. OpenSSL 3.6 is affected. Remediation: OpenSSL 3.6 users should upgrade to 3.6.2. 3. Potential Use-After-Free in DANE Client Code (CVE-2026-28287) Severity: Low Vulnerability Overview: When a client performs DANE TLSA base validation, pairing with an unusual server DANE TLSA record may lead to a use-after-free or double-free on the client side. Affected Versions: OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, and 1.1.1 are affected. OpenSSL 1.0.2 is not affected. Remediation: OpenSSL 3.6 users should upgrade to 3.6.2. OpenSSL 3.5 users should upgrade to 3.5.6. OpenSSL 3.4 users should upgrade to 3.4.5. OpenSSL 3.3 users should upgrade to 3.3.7. OpenSSL 3.0 users should upgrade to 3.0.20. OpenSSL 1.1.1 users should upgrade to 1.1.1zg (Extended Support customers only). 4. NULL Pointer Dereference When Processing Delta CRLs (CVE-2026-28388) Severity: Low Vulnerability Overview: When processing a Delta CRL containing a Delta CRL Indicator extension, a NULL pointer dereference may occur if the required CRL Number extension is missing, leading to a crash or denial of service. Affected Versions: OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1, and 1.0.2 are affected. FIPS Module 3.6, 3.5, 3.4, 3.3, and 3.0 are not affected. Remediation: OpenSSL 3.6 users should upgrade to 3.6.2. OpenSSL 3.5 users should upgrade to 3.5.6. OpenSSL 3.4 users should upgrade to 3.4.5. OpenSSL 3.3 users should upgrade to 3.3.7. OpenSSL 3.0 users should upgrade to 3.0.20. OpenSSL 1.1.1 users should upgrade to 1.1.1zg (Extended Support customers only). OpenSSL 1.0.2 users should upgrade to 1.0.2p (Extended Support customers only). 5. Possible NULL Dereference When Processing CMS KeyAgreeRecipientInfo (CVE-2026-28389) Severity: Low Vulnerability Overview: When processing an encrypted CMS encryption packet containing KeyAgreeRecipientInfo, a NULL pointer dereference may occur if the optional parameter field KeyEncryptionAlgorithmIdentifier is missing, leading to a crash or denial of service. Affected Versions: OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1, and 1.0.2 are affected. FIPS Module 3.6, 3.5, 3.4, 3.3, and 3.0 are not affected. Remediation: OpenSSL 3.6 users should upgrade to 3.6.2. OpenSSL 3.5 users should upgrade to 3.5.6. OpenSSL 3.4 users should upgrade to 3.4.5. OpenSSL 3.3 users should upgrade to 3.3.7. OpenSSL 3.0 users should upgrade to 3.0.20. OpenSSL 1.1.1 users should upgrade to 1.1.1zg (Extended Support customers only). OpenSSL 1.0.2 users should upgrade to 1.0.2p (Extended Support customers only).

Goal Reached Thanks to every supporter — we hit 100%!

OpenSSL Security Advisory: Fixes for CVE-2026-31790 Memory Leak, OOB Read, and UAF