{
  "cveId": "CVE-2026-42305",
  "url": "https://patchblox.com/security/cve/CVE-2026-42305",
  "summary": "CVE-2026-42305 is fixed in 4 products on 1 platform, first by ALAS2023-2026-2026, released August 3, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "python3-dulwich: Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities:\nCVE-2026-47734:\n\tAn uncon...",
  "description": "Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities:\nCVE-2026-47734:\n\tAn uncontrolled-resource-consumption (memory exhaustion) denial-of-service vulnerability (CWE-400 / CWE-789).\n\nA client with push access could push a tiny crafted thin pack (~174 bytes) whose delta header declares a huge dest_size. When dulwich ingested it via add_thin_pack / apply_delta, it would allocate hundreds of MB of memory based on that attacker-controlled size, with no relationship to the actual bytes received.\n\nWho is impacted: Operators running a dulwich-based Git server that exposes git-receive-pack (i.e. accepts pushes) -\nfor example via dulwich.server functionality, the HTTP smart server, or anything built on ReceivePackHandler.\n\nCVE-2026-42305:\n\tArbitrary file write leading to remote code execution when cloning or checking out a malicious Git repository on Windows.\n\nDulwich\u0027s path-element validator accepted tree entries whose filenames contained bytes that Windows interprets as structural path syntax:\n\n\\ -- the Windows path separator. A single tree entry named .git\\hooks\\pre-commit.exe was treated as one valid filename on POSIX but materialized as nested directories .git/hooks/pre-commit.exe on Windows, planting a file inside the victim\u0027s .git directory. Git for Windows then\nexecutes that hook on the next git commit, giving the attacker arbitrary code execution in the victim\u0027s user context. The same primitive can be used with ..\\outside.txt to escape the work tree.\n: -- the NTFS alternate-data-stream marker. .git::$INDEX_ALLOCATION writes directly into the victim\u0027s .git entity, bypassing the .git-as-a-directory check.\ngit~ -- NTFS 8.3 short-name aliases of .git. Only the literal git1 was rejected; git2, git10, GIT1, etc. were all accepted.\nContributing configuration bugs made matters worse. The core.protectNTFS and core.protectHFS settings were looked up under a wrong option name and so user-set values were silently ignored, and core.protectNTFS only defaulted to true on Windows (Git upstream has defaulted it to true everywhere since CVE-2019-1353). Both have been corrected.\n\nAnyone who clones, fetches, or checks out an untrusted repository with Dulwich on Windows - either through the Dulwich CLI, porcelain.clone, or any downstream tool built on Dulwich - is impacted. POSIX clones are not directly exploitable (on POSIX \\ is a literal filename byte), but a POSIX user can unknowingly propagate a malicious tree to Windows consumers via push or re-publication.\n\nCVE-2026-38974:\n\tDulwich through 1.1.0 was found to be missing SSH host key verification in contrib/paramiko_vendor.py.",
  "published": "2026-08-03T09:00:00Z",
  "severity": "important",
  "epss": 0.00635,
  "epssPercentile": 0.50747,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "python-dulwich-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "0.20.18-1.amzn2023.0.3",
      "fix": "ALAS2023-2026-2026",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2026",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python-dulwich-doc",
      "release": "amzn 2023",
      "fixedVersion": "0.20.18-1.amzn2023.0.3",
      "fix": "ALAS2023-2026-2026",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2026",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-dulwich",
      "release": "amzn 2023",
      "fixedVersion": "0.20.18-1.amzn2023.0.3",
      "fix": "ALAS2023-2026-2026",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2026",
      "released": "2026-08-03T09:00:00Z"
    },
    {
      "platform": "linux",
      "product": "python3-dulwich-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "0.20.18-1.amzn2023.0.3",
      "fix": "ALAS2023-2026-2026",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-2026",
      "released": "2026-08-03T09:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-10T01:44:33Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}