← Back to CVE Explorer

CVE-2026-52936

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: jitterentropy - replace long-held spinlock with mutex jent_kcapi_random() serializes the shared jitterentropy state, but it currently holds a spinlock across the jent_read_entropy() call. That path performs expensive jitter collection and SHA3 conditioning, so parallel readers can trigger stalls as contending waiters spin for the same lock. To prevent non-preemptible lock hold, replace rng->jent_lock with a mutex so contended readers sleep instead of spinning on a shared lock held across expensive entropy generation.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-24 08:16:23.883000
Last modified
2026-10-30 13:19:04.473000
View original CVE JSON 
{
  "id": "CVE-2026-52936",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-24T08:16:23.883",
  "lastModified": "2026-10-30T13:19:04.473",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: jitterentropy - replace long-held spinlock with mutex\n\njent_kcapi_random() serializes the shared jitterentropy state, but it\ncurrently holds a spinlock across the jent_read_entropy() call. That\npath performs expensive jitter collection and SHA3 conditioning, so\nparallel readers can trigger stalls as contending waiters spin for\nthe same lock.\n\nTo prevent non-preemptible lock hold, replace rng->jent_lock with a\nmutex so contended readers sleep instead of spinning on a shared lock\nheld across expensive entropy generation."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ncrypto: jitterentropy - reemplazar el spinlock de larga duración con un mutex\n\njent_kcapi_random() serializa el estado compartido de jitterentropy, pero actualmente mantiene un spinlock a lo largo de la llamada a jent_read_entropy(). Esa ruta realiza una costosa recolección de jitter y acondicionamiento SHA3, por lo que los lectores paralelos pueden provocar bloqueos mientras los esperadores en contención giran por el mismo bloqueo.\n\nPara evitar la retención de bloqueo no preemptiva, reemplazar rng  ->  jent_lock con un mutex para que los lectores en contención duerman en lugar de girar en un bloqueo compartido mantenido a lo largo de la costosa generación de entropía."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "crypto/jitterentropy-kcapi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "21de77d06f6b540e870e64ef5ff56be4eb8ba08f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "18216b8ab6904753eaf31baf453cb02ecd202ba4",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "4c03e6eb98443dc4d6d422a9780034a5b75376b4",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "ff734dbd9e2432601a6dcd167cfb0bf8a36d1880",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "ec427dc5286da1ed08f2d510e2147a7581b0cb02",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bb5530e4082446aac3a3d69780cd4dbfa4520013",
              "lessThan": "01d798e9feb30212952d4e992801ba6bd6a82351",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "crypto/jitterentropy-kcapi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4.2",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "4.2",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.141",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.91",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.33",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.0.10",
              "lessThanOrEqual": "7.0.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "4.2",
              "versionEndExcluding": "6.6.141",
              "matchCriteriaId": "EF97161C-1BB5-4ADC-A7BA-2A18D7A44511"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.7",
              "versionEndExcluding": "6.12.91",
              "matchCriteriaId": "C918746B-DE6F-448F-A93E-A04C5481688D"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.13",
              "versionEndExcluding": "6.18.33",
              "matchCriteriaId": "96D99E49-380D-43AB-BDBA-25C3AD018A9C"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "6.19",
              "versionEndExcluding": "7.0.10",
              "matchCriteriaId": "A13475D2-59BF-4716-94B5-7C1D239A2CF4"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/01d798e9feb30212952d4e992801ba6bd6a82351",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/18216b8ab6904753eaf31baf453cb02ecd202ba4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/21de77d06f6b540e870e64ef5ff56be4eb8ba08f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4c03e6eb98443dc4d6d422a9780034a5b75376b4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/ec427dc5286da1ed08f2d510e2147a7581b0cb02",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/ff734dbd9e2432601a6dcd167cfb0bf8a36d1880",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ]
    }
  ]
}