{
  "crds_version": "0.1",
  "kind": "base",
  "id": "crds:cve-2025-39964",
  "revision": 1,
  "title": "Linux Kernel — Race Condition in Crypto Socket Writes",
  "summary": "A race condition in the Linux kernel's user-space crypto socket interface lets a local user issue overlapping writes to one socket, corrupting its internal state and crashing or destabilizing the host. Exploitation has been observed in the wild.",
  "source_type": "cve",
  "severity": "high",
  "cvss": {
    "score": 5.5,
    "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "version": "3.1"
  },
  "epss": 0.0079,
  "exploitation": {
    "known_exploited": true,
    "exploit_available": false,
    "attack_complexity": "low",
    "kev_added": "2026-09-18",
    "prerequisites": "Local access as a low-privileged user able to open kernel crypto user-space sockets"
  },
  "remediation": {
    "patch_available": true
  },
  "mitre_attack": [
    "T1499"
  ],
  "kill_chain": "impact",
  "recommended_action": "Update to a distribution kernel carrying the af_alg concurrent-write fix now; prioritize shared and multi-user hosts, since exploitation has been observed in the wild.",
  "confidence": "medium",
  "provenance": [
    {
      "fields": [
        "cvss",
        "exploitation.attack_complexity",
        "exploitation.exploit_available",
        "references",
        "published_at"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
      "retrieved_at": "2026-09-20T10:52:56.734Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "exploitation.known_exploited",
        "exploitation.kev_added"
      ],
      "source": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "retrieved_at": "2026-09-20T10:52:56.734Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "epss"
      ],
      "source": "https://api.first.org/data/v1/epss?cve=CVE-2025-39964",
      "retrieved_at": "2026-09-20T10:52:56.734Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
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        "summary",
        "severity",
        "remediation",
        "mitre_attack",
        "kill_chain",
        "recommended_action",
        "confidence",
        "tags",
        "exploitation.prerequisites"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
      "retrieved_at": "2026-09-20T10:52:56.734Z",
      "confidence": "high",
      "extractor": "claude-code"
    },
    {
      "fields": [
        "tags"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
      "retrieved_at": "2026-09-20T11:09:51.520Z",
      "confidence": "high",
      "extractor": "human"
    }
  ],
  "references": [
    {
      "type": "cve",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
      "label": "NVD record"
    },
    {
      "type": "cisa",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "label": "CISA Known Exploited Vulnerabilities catalog"
    },
    {
      "type": "vendor_advisory",
      "url": "https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce"
    },
    {
      "type": "vendor_advisory",
      "url": "https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285"
    },
    {
      "type": "vendor_advisory",
      "url": "https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8"
    }
  ],
  "published_at": "2025-10-13T14:15:34.737Z",
  "issued_at": "2026-09-20T10:52:56.734Z",
  "tags": [
    "linux",
    "kernel",
    "race-condition",
    "denial-of-service",
    "cryptography"
  ]
}