CVE-2025-39802
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-15

Last updated on: 2025-11-24

Assigner: kernel.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.
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Meta Information
Published
2025-09-15
Last Modified
2025-11-24
Generated
2026-05-27
AI Q&A
2025-09-15
EPSS Evaluated
2026-05-25
NVD
CVE-2025-39802
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
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KEV
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CWE ID Description
CWE-NVD-CWE-noinfo
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's crypto library (specifically in the arm/poly1305 implementation) involves register corruption in contexts where SIMD (Single Instruction, Multiple Data) instructions are not available or usable. A safety check that ensures SIMD usability was removed, which could lead to the Poly1305 functions corrupting random tasks' registers or computing incorrect Message Authentication Codes (MACs) if called when SIMD registers are unusable. The fix restores this safety check to prevent such corruption and incorrect computations.


How can this vulnerability impact me? :

If exploited, this vulnerability can cause corruption of CPU registers belonging to unrelated tasks and result in incorrect cryptographic MAC computations. This could lead to data integrity issues or unpredictable system behavior in environments relying on the affected Poly1305 cryptographic functions on ARM architectures without SIMD support.


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