How severe is GHSA-wccx-j62j-r448?

No CVSS score has been assigned to GHSA-wccx-j62j-r448 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-wccx-j62j-r448?

GHSA-wccx-j62j-r448 affects the following packages: fickling (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-wccx-j62j-r448?

Update fickling to 0.1.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wccx-j62j-r448 is resolved across your whole dependency graph.

How do I detect GHSA-wccx-j62j-r448 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-wccx-j62j-r448 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-wccx-j62j-r448?

O3 pinpoints whether GHSA-wccx-j62j-r448 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-wccx-j62j-r448 actively exploited in the wild?

No public exploit code has been indexed for GHSA-wccx-j62j-r448 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.

When was GHSA-wccx-j62j-r448 published, and has it been updated?

GHSA-wccx-j62j-r448 was published on March 4, 2026 and was last updated on March 4, 2026. 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-wccx-j62j-r448

Fickling has `always_check_safety()` bypass: pickle.loads and _pickle.loads remain unhooked

Published

Mar 4, 2026

Updated

Mar 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

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

Assessment

The missing pickle entrypoints pickle.loads, _pickle.loads, and _pickle.load were added to the hook https://github.com/trailofbits/fickling/commit/8c24c6edabceab156cfd41f4d70b650e1cdad1f7.

Original report

Summary

fickling.always_check_safety() does not hook all pickle entry points. pickle.loads, _pickle.loads, and _pickle.load remain unprotected, enabling malicious payload execution despite global safety mode being enabled.

Affected versions

<= 0.1.8 (verified on current upstream HEAD as of 2026-03-03)

Non-duplication check against published Fickling GHSAs

No published advisory covers hook-coverage bypass in run_hook(). Existing advisories are blocklist/detection bypasses (runpy, pty, cProfile, marshal/types, builtins, network constructors, OBJ visibility, etc.), not runtime hook coverage parity.

Root cause

run_hook() patches only:

pickle.load
pickle.Unpickler
_pickle.Unpickler

It does not patch:

pickle.loads
_pickle.load
_pickle.loads

Reproduction (clean upstream)

import io, pickle, _pickle
from unittest.mock import patch
import fickling
from fickling.exception import UnsafeFileError

class Payload:
    def __reduce__(self):
        import subprocess
        return (subprocess.Popen, (['echo','BYPASS'],))

data = pickle.dumps(Payload())
fickling.always_check_safety()

# Bypass path
with patch('subprocess.Popen') as popen_mock:
    pickle.loads(data)
    print('bypass sink called?', popen_mock.called)  # True

# Control path is blocked
with patch('subprocess.Popen') as popen_mock:
    try:
        pickle.load(io.BytesIO(data))
    except UnsafeFileError:
        pass
    print('blocked sink called?', popen_mock.called)  # False

Observed on vulnerable code:

pickle.loads executes payload
pickle.load is blocked

Minimal patch diff

--- a/fickling/hook.py
+++ b/fickling/hook.py
@@
 def run_hook():
-    pickle.load = loader.load
+    pickle.load = loader.load
+    _pickle.load = loader.load
+    pickle.loads = loader.loads
+    _pickle.loads = loader.loads

Validation after patch

pickle.loads, _pickle.loads, and _pickle.load all raise UnsafeFileError
sink not called in any path

Regression tests added locally:

test_run_hook_blocks_pickle_loads
test_run_hook_blocks__pickle_load_and_loads in test/test_security_regressions_20260303.py

Impact

High-confidence runtime protection bypass for applications that trust always_check_safety() as global guard.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`fickling`	all versions	0.1.9

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 0.1.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wccx-j62j-r448 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-wccx-j62j-r448 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-wccx-j62j-r448. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Assessment The missing pickle entrypoints `pickle.loads`, `_pickle.loads`, and `_pickle.load` were added to the hook https://github.com/trailofbits/fickling/commit/8c24c6edabceab156cfd41f4d70b650e1cdad1f7. # Original report ## Summary `fickling.always_check_safety()` does not hook all pickle entry points. `pickle.loads`, `_pickle.loads`, and `_pickle.load` remain unprotected, enabling malicious payload execution despite global safety mode being enabled. ## Affected versions `<= 0.1.8` (verified on current upstream HEAD as of 2026-03-03) ## Non-duplication check against published Ficklin

O3 Security · Impact-Aware SCA

Is GHSA-wccx-j62j-r448 in your dependencies?

O3 detects GHSA-wccx-j62j-r448 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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