CVE-2023-6129 Openssl CVE debrief

Who should care

Administrators and developers using OpenSSL on PowerPC systems with vector-instruction support should review this CVE, especially if their applications may negotiate ChaCha20-Poly1305 for TLS 1.2 or 1.3. Security teams should prioritize environments running affected OpenSSL versions on newer PowerPC hardware, and application owners should care if process stability or correct computation depends on preserved vector-register state.

Technical summary

According to the vendor advisory and NVD, the POLY1305 MAC implementation for PowerPC restores vector-register contents in a different order than they are saved. As a result, some vector registers can be corrupted when control returns to the caller. NVD maps the issue to CWE-787, while OpenSSL also associates it with CWE-440. The vulnerability is relevant only on PowerPC CPUs with the newer PowerISA 2.07 vector instruction set. NVD’s affected-version criteria list OpenSSL 3.0.0 through 3.0.12, 3.1.0 through 3.1.4, and 3.2.0.

Defensive priority

Medium. The bug is architecture-specific and requires a PowerPC system with vector-instruction support, but it can affect application correctness, stability, and in some cases process control depending on how the caller uses vector registers. For TLS servers, client-controlled cipher negotiation can influence whether the affected ChaCha20-Poly1305 path is used.

Recommended defensive actions

• Upgrade OpenSSL to a fixed release that includes the vendor patches referenced in the OpenSSL security advisory.
• Verify whether any production systems run OpenSSL on PowerPC hardware with PowerISA 2.07 support.
• Check whether TLS servers permit ChaCha20-Poly1305 and review cipher configuration where appropriate.
• Prioritize testing for application crashes, incorrect calculations, or state-corruption symptoms on affected platforms.
• If you maintain downstream packages or appliances, confirm that the patched OpenSSL commits have been incorporated into your vendor build.

Evidence notes

This debrief is based on the NVD record, the OpenSSL security advisory, and the referenced OpenSSL patch commits. The vendor advisory states that the issue can corrupt internal application state on PowerPC platforms with vector instructions and classifies the issue as low severity. NVD published the same CVE on 2024-01-09, assigns CVSS 3.1 vector AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H, and lists affected OpenSSL version ranges in its CPE criteria. The provided references include three OpenSSL patch commits and the vendor advisory, which together support the mitigation guidance.

Official resources