In the Linux kernel, the following vulnerability has been resolved: lib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts Restore the SIMD usability check that was removed by commit 773426f4771b ("crypto: arm/poly1305 - Add block-only interface"). This safety check is cheap and is well worth eliminating a footgun. While the Poly1305 functions should not be called when SIMD registers are unusable, if they are anyway, they should just do the right thing instead of corrupting random tasks' registers and/or computing incorrect MACs. Fixing this is also needed for poly1305_kunit to pass. Just use may_use_simd() instead of the original crypto_simd_usable(), since poly1305_kunit won't rely on crypto_simd_disabled_for_test.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/52c3e242f4d0043186b70d65460ba1767f27494a cve-icon cve-icon
https://git.kernel.org/stable/c/87bdfba903be7084cb3ee04032b14a81181fe413 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025091551-CVE-2025-39802-fba9@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-39802 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-39802 cve-icon
History

Wed, 17 Sep 2025 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Tue, 16 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Mon, 15 Sep 2025 13:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: lib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts Restore the SIMD usability check that was removed by commit 773426f4771b ("crypto: arm/poly1305 - Add block-only interface"). This safety check is cheap and is well worth eliminating a footgun. While the Poly1305 functions should not be called when SIMD registers are unusable, if they are anyway, they should just do the right thing instead of corrupting random tasks' registers and/or computing incorrect MACs. Fixing this is also needed for poly1305_kunit to pass. Just use may_use_simd() instead of the original crypto_simd_usable(), since poly1305_kunit won't rely on crypto_simd_disabled_for_test.
Title lib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-09-15T12:36:44.792Z

Updated: 2025-09-15T12:36:44.792Z

Reserved: 2025-04-16T07:20:57.134Z

Link: CVE-2025-39802

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-15T13:15:35.703

Modified: 2025-09-15T15:21:42.937

Link: CVE-2025-39802

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-15T00:00:00Z

Links: CVE-2025-39802 - Bugzilla