FKIE_CVE-2026-64846

Vulnerability from fkie_nvd - Published: 2026-08-20 17:19 - Updated: 2026-08-20 20:17
Severity
2.8 (Low) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
Summary
Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0.
References
security-advisories@github.comhttps://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390
security-advisories@github.comhttps://github.com/NixOS/nix/pull/15401
security-advisories@github.comhttps://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "nix",
          "vendor": "NixOS",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.35.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user\u0027s permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0."
    }
  ],
  "id": "CVE-2026-64846",
  "lastModified": "2026-08-20T20:17:45.813",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 2.8,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.1,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-64846",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-20T19:32:14.918442Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-20T17:19:16.813",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/NixOS/nix/pull/15401"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-61"
        },
        {
          "lang": "en",
          "value": "CWE-367"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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