CVE-2025-70559 Insecure Deserialization (pickle) in pdfminer.six CMap Loader — Local Privesc
An attacker can achieve arbitrary code execution or privilege escalation by placing a malicious pickle file in a location accessible to the pdfminer.six library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-70559?
CVE-2025-70559 is a medium-severity unsafe deserialization vulnerability in n/a, published on 3 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
pdfminer.six before 20251230 contains an insecure deserialization vulnerability in the CMap loading mechanism. The library uses Python pickle to deserialize CMap cache files without validation. An attacker with the ability to place a malicious pickle file in a location accessible to the application can trigger arbitrary code execution or privilege escalation when the file is loaded by a trusted process. This is caused by an incomplete patch to CVE-2025-64512.
Weakness: CWE-502
Which versions are affected by CVE-2025-70559?
3 open source packages ship an affected version, including pdfminer-six and pdfminer.six.
| Package | Affected | Fixed in |
|---|---|---|
pdfminer-six PyPI | All versions | 20251230 |
pdfminer-six PyPI | All versions | 20251230 |
pdfminer.six PyPI | All versions | 20251230 |
How do I fix CVE-2025-70559?
Upgrade pdfminer-six to 20251230 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-70559 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-70559 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as DEBIAN-CVE-2025-70559, DLA-4374-2, GHSA-f83h-ghpp-7wcc, OESA-2026-4210, OESA-2026-4211, PYSEC-2026-1761 and 1 more.