CVE-2025-71339 Picklescan - Arbitrary Code Execution via numpy.f2py.crackfortran._eval_length Gadget
Attackers can bypass Picklescan's safety checks to execute arbitrary code via malicious pickle files using a specific numpy gadget.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-71339?
CVE-2025-71339 is a high-severity unsafe deserialization vulnerability in Picklescan, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Picklescan before 0.0.33 fails to detect the numpy.f2py.crackfortran._eval_length gadget in pickle __reduce__ methods, allowing arbitrary code execution. Attackers can craft malicious pickle files that execute arbitrary Python code when loaded by victims who trust Picklescan's safety validation.
Weakness: CWE-502
Which versions are affected by CVE-2025-71339?
3 open source packages ship an affected version, including picklescan.
| Package | Affected | Fixed in |
|---|---|---|
picklescan PyPI | All versions | 0.0.33 |
picklescan PyPI | All versions | 0.0.33 |
picklescan PyPI | All versions | 0.0.33 |
How do I fix CVE-2025-71339?
Upgrade picklescan to 0.0.33 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-71339 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-71339 exists.
Sources
Also known as GHSA-6556-fwc2-fg2p, PYSEC-2026-1783.