CVE-2023-6129 | POLY1305 MAC implementation corrupts vector registers on PowerPC

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.

Published: 2024-01-09 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-6129 is rated Moderate Risk (53.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.32%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-6129

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 3.33% 2.32% -1.01%
2 2026-06-02 3.42% 3.33% -0.09%
3 2026-05-22 — 3.42% —

Full EPSS history (31 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-6129

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 4.2 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 4.2 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-6129

GitHub Security Advisory for CVE-2023-6129

GHSA-rj8q-prqp-jwfg · Severity: medium — Issue summary: The POLY1305 MAC (message authentication code) implementation contains a bug that...

OS Trackers for CVE-2023-6129

vendor priority summary link
alpine — CVE-2023-6129: 1 source package rows (openssl); 113 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 24, open 89. https://security.alpinelinux.org/vuln/CVE-2023-6129
debian unimportant CVE-2023-6129 unimportant priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-6129
redhat low — https://access.redhat.com/security/cve/CVE-2023-6129
suse medium CVE-2023-6129 severity moderate: SUSE including 81 source package names (compat-openssl098, edk2-ovmf-20240524-6.el9_5, …), 535 product×package rows across 62 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7.1, … (62 product lines)): Known Not Affected 455, Fixed 80. https://www.suse.com/security/cve/CVE-2023-6129/
ubuntu low CVE-2023-6129 low priority: Ubuntu including 4 source packages (edk2, nodejs, openssl, openssl1.0), 48 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 24, DNE 10, released 7, ignored 3, needs-triage 3, needed 1. https://ubuntu.com/security/CVE-2023-6129

Affected software / configurations for CVE-2023-6129

Vendor Product Version Raw CPE
openssl openssl >= 3.0.0, <= 3.0.12 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl >= 3.1.0, <= 3.1.4 cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
openssl openssl 3.2.0 cpe:2.3:a:openssl:openssl:3.2.0:*:*:*:*:*:*:*

References for CVE-2023-6129

URL Tags
https://github.com/openssl/openssl/commit/050d26383d4e264966fb83428e72d5d48f402d35 Patch
https://github.com/openssl/openssl/commit/5b139f95c9a47a55a0c54100f3837b1eee942b04 Patch
https://github.com/openssl/openssl/commit/f3fc5808fe9ff74042d639839610d03b8fdcc015 Patch
https://www.openssl.org/news/secadv/20240109.txt Vendor Advisory
http://www.openwall.com/lists/oss-security/2024/03/11/1
https://security.netapp.com/advisory/ntap-20240216-0009/
https://security.netapp.com/advisory/ntap-20240426-0008/
https://security.netapp.com/advisory/ntap-20240426-0013/
https://security.netapp.com/advisory/ntap-20240503-0011/
https://cert-portal.siemens.com/productcert/html/ssa-265688.html
https://cert-portal.siemens.com/productcert/html/ssa-331112.html
https://cert-portal.siemens.com/productcert/html/ssa-769027.html
https://cert-portal.siemens.com/productcert/html/ssa-915275.html
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