CVE-2025-71359 picklescan - Unsafe Deserialization via lib2to3.pgen2.grammar.Grammar.loads
Attackers can bypass picklescan detection to execute arbitrary code via malicious pickle payloads using lib2to3 grammar loading.
- 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
- None listed
What is CVE-2025-71359?
CVE-2025-71359 is a high-severity unsafe deserialization vulnerability in picklescan, published on 4 Jul 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 0.0.29 fails to detect malicious pickle payloads that utilize lib2to3.pgen2.grammar.Grammar.loads in the reduce method, allowing remote code execution. Attackers can craft pickle files embedding dangerous code that evades picklescan detection and executes during pickle.load() deserialization.
Weakness: CWE-502
Which versions are affected by CVE-2025-71359?
2 open source packages ship an affected version, including picklescan.
| Package | Affected | Fixed in |
|---|---|---|
picklescan PyPI | All versions | 0.0.29 |
picklescan PyPI | All versions | 0.0.29 |
How do I fix CVE-2025-71359?
Upgrade picklescan to 0.0.29 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-71359 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-71359 exists.
Sources
Also known as GHSA-f54q-57x4-jg88, GHSA-vp8m-mf3r-82q9.