OpenSSL 3.6.2 Patches Eight CVEs, Including Moderate RSA KEM and AES‑CFB‑128 Flaws
What It Is – OpenSSL 3.6.2 is a maintenance release that addresses eight security vulnerabilities across cryptographic primitives, certificate handling, and CMS processing. The most severe issue is rated Moderate (CVE‑2026‑31790 – RSA KEM encapsulation failure).
Exploitability – None of the disclosed CVEs have publicly‑available exploit code, and no active exploitation has been reported. However, several bugs (out‑of‑bounds read, use‑after‑free, heap overflow) could be weaponised by a skilled attacker in a targeted scenario. CVSS scores range from 5.3 – 7.2.
Affected Products – OpenSSL 3.6.x and 3.5.x are vulnerable; earlier branches (3.4, 3.3, 3.0, 1.0.2, 1.1.1) are not impacted by all eight CVEs. The AES‑CFB‑128 out‑of‑bounds read specifically affects x86‑64 CPUs with AVX‑512 enabled.
TPRM Impact –
- A widely‑used cryptographic library means any downstream SaaS, cloud, or on‑premise service that embeds OpenSSL 3.6.x could inherit the flaws.
- Potential data confidentiality or integrity loss if an attacker exploits the RSA KEM or AES‑CFB‑128 bugs in a supply‑chain context.
- Regression fixes (X509_V_FLAG_CRL_CHECK_ALL, stapled OCSP handling) indicate that older versions may experience service disruptions after upgrade.
Recommended Actions –
- Inventory all assets (servers, containers, appliances) running OpenSSL 3.6.x or 3.5.x.
- Prioritize patching for systems with AVX‑512 enabled CPUs to mitigate CVE‑2026‑28386.
- Test the update in a staging environment to verify regression fixes (CRL flag, OCSP stapling).
- For long‑term stability, consider migrating to the LTS 3.5 branch or later LTS releases.
- Update third‑party risk registers to reflect the new vulnerability status and communicate the patch requirement to vendors.