{"id":"CVE-2025-39802","summary":"lib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlib/crypto: arm/poly1305: Fix register corruption in no-SIMD contexts\n\nRestore the SIMD usability check that was removed by commit 773426f4771b\n(\"crypto: arm/poly1305 - Add block-only interface\").\n\nThis safety check is cheap and is well worth eliminating a footgun.\nWhile the Poly1305 functions should not be called when SIMD registers\nare unusable, if they are anyway, they should just do the right thing\ninstead of corrupting random tasks' registers and/or computing incorrect\nMACs.  Fixing this is also needed for poly1305_kunit to pass.\n\nJust use may_use_simd() instead of the original crypto_simd_usable(),\nsince poly1305_kunit won't rely on crypto_simd_disabled_for_test.","modified":"2026-04-02T12:48:09.732394Z","published":"2025-09-15T12:36:44.792Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39802.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/52c3e242f4d0043186b70d65460ba1767f27494a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/87bdfba903be7084cb3ee04032b14a81181fe413"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39802.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39802"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"773426f4771bdd82ac5c834bf4c1775315c73a46"},{"fixed":"87bdfba903be7084cb3ee04032b14a81181fe413"},{"fixed":"52c3e242f4d0043186b70d65460ba1767f27494a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39802.json"}}],"schema_version":"1.7.5"}