# CVE-2023-6129: POLY1305 MAC implementation corrupts vector registers on PowerPC > A bug in OpenSSL's POLY1305 implementation on PowerPC corrupts vector registers, potentially causing crashes or code execution in TLS servers. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 9 Jan 2024 - **Updated:** 14 Oct 2026 - **Also known as:** ALPINE-CVE-2023-6129, AZL-35044, AZL-35085, AZL-42697, AZL-42754, AZL-47643, AZL-78582, CLEANSTART-2026-MW33481, DEBIAN-CVE-2023-6129, GHSA-rj8q-prqp-jwfg, JLSEC-2026-245, UBUNTU-CVE-2023-6129 ## What is CVE-2023-6129? CVE-2023-6129 is a medium-severity memory corruption vulnerability in Openssl Openssl, published on 9 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Issue summary: The POLY1305 MAC (message authentication code) implementation contains a bug that might corrupt the internal state of applications running on PowerPC CPU based platforms if the CPU provides vector instructions. Impact summary: If an attacker can influence whether the POLY1305 MAC algorithm is used, the application state might be corrupted with various application dependent consequences. The POLY1305 MAC (message authentication code) implementation in OpenSSL for PowerPC CPUs restores the contents of vector registers in a different order than they are saved. Thus the contents of some of these vector registers are corrupted when returning to the caller. The vulnerable code is used only on newer PowerPC processors supporting the PowerISA 2.07 instructions. The consequences of this kind of internal application state corruption can be various - from no consequences, if the calling application does not depend on the contents of non-volatile XMM registers at all, to the worst consequences, where the attacker could get complete control of the application process. However unless the compiler uses the vector registers for storing pointers, the most likely consequence, if any, would be an incorrect result of some application dependent calculations or a crash leading to a denial of service. The POLY1305 MAC algorithm is most frequently used as part of the CHACHA20-POLY1305 AEAD (authenticated encryption with associated data) algorithm. The most common usage of this AEAD cipher is with TLS protocol versions 1.2 and 1.3. If this cipher is enabled on the server a malicious client can influence whether this AEAD cipher is used. This implies that TLS server applications using OpenSSL can be potentially impacted. However we are currently not aware of any concrete application that would be affected by this issue therefore we consider this a Low severity security issue. Weakness: CWE-787 (Out-of-bounds Write), CWE-440 (Expected Behavior Violation) ## Which versions are affected by CVE-2023-6129? It affects 1 product. Products: Openssl Openssl. ## How do I fix CVE-2023-6129? Apply the vendor's patch. ## Is CVE-2023-6129 being exploited? There is no known exploitation of CVE-2023-6129 in the wild and no public exploit code. ## Other vulnerabilities in Openssl Openssl - [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0) - [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0) - [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8) - [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8) - [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-6129 and fix it if it is affected. What it is: CVE-2023-6129 is a medium-severity memory corruption vulnerability in Openssl Openssl, published on 9 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-6129 in the wild and no public exploit code. Affected product: Openssl Openssl. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2023-6129/ (Markdown: https://insights.sbomify.com/CVE-2023-6129/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6129 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6129 - OSV: https://osv.dev/vulnerability/CVE-2023-6129 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-6129/ Summaries are generated and may contain mistakes; the official description above is the record.