Riskcovery

CVE-2025-39802

lib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts

State
Published
Severity
7.5 High
Published
Sep 15, 2025
Updated
Aug 5, 2026
Reserved
Apr 16, 2025

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HLinux

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • 773426f4771bdd82ac5c834bf4c1775315c73a46 to before 87bdfba903be7084cb3ee04032b14a81181fe413Affected
  • 773426f4771bdd82ac5c834bf4c1775315c73a46 to before 52c3e242f4d0043186b70d65460ba1767f27494aAffected
LinuxLinux
  • 6.16Affected
  • before 6.16Not affected
  • 6.16.4 through 6.16.*Not affected
  • 6.17 and laterNot affected

References

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