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CVE-2025-39802

Full vulnerability record from the local CVENow database.

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.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-15 13:15:35.703000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON
{
  "id": "CVE-2025-39802",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-09-15T13:15:35.703",
  "lastModified": "2026-10-19T21:10:00.160",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nlib/crypto: arm/poly1305: Corrección de la corrupción de registros en contextos sin SIMD\n\nRestaurar la comprobación de usabilidad de SIMD que fue eliminada por el commit 773426f4771b ('crypto: arm/poly1305 - Añadir interfaz solo de bloque').\n\nEsta comprobación de seguridad es económica y bien vale la pena eliminar un riesgo de error autoinfligido. Si bien las funciones Poly1305 no deberían ser llamadas cuando los registros SIMD no son utilizables, si lo son de todos modos, deberían simplemente hacer lo correcto en lugar de corromper los registros de tareas aleatorias y/o calcular MACs incorrectos. Corregir esto también es necesario para que poly1305_kunit pase.\n\nSimplemente usar may_use_simd() en lugar del original crypto_simd_usable(), ya que poly1305_kunit no dependerá de crypto_simd_disabled_for_test."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
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          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "lib/crypto/arm/poly1305-glue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "git",
              "status": "affected"
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          "product": "Linux",
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          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
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              "status": "affected"
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              "version": "0",
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              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.16.4",
              "lessThanOrEqual": "6.16.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.17",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
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          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
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          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
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  "weaknesses": [
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      "type": "Primary",
      "description": [
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          "value": "NVD-CWE-noinfo"
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  "references": [
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      "url": "https://git.kernel.org/stable/c/52c3e242f4d0043186b70d65460ba1767f27494a",
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}