{
  "id": "CVE-2025-39964",
  "url": "https://spydr.io/cve/CVE-2025-39964",
  "published": "2025-10-13T14:15:34.737Z",
  "modified": "2026-09-19T04:17:48.307Z",
  "score": 5.5,
  "severity": "medium",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "score_source": "NVD",
  "epss": 0.01276,
  "epss_percentile": 0.68944,
  "exploited": true,
  "kev": {
    "added": "2026-09-18",
    "due": "2026-09-21",
    "action": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
    "ransomware": "Unknown",
    "name": "Linux Kernel Race Condition Vulnerability",
    "notes": "This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce; https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9; https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8; https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84; https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d; https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042; https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2025-39964"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Linux",
    "Siemens"
  ],
  "products": [
    "Linux",
    "Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
    "Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
    "Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP"
  ],
  "cwes": [
    "CWE-362"
  ],
  "description": "In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg Issuing two writes to the same af_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, concurrent writes may create inconsistencies in the internal socket state. Disallow this by adding a new ctx->write field that indiciates exclusive ownership for writing.",
  "status": "Analyzed",
  "score_type": "Primary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 5.5,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39964",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}