Arbitrary Code Execution in pdfminer.six via Crafted PDF Input

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.6 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS

• CVE-2025-64512: 0.33% estimated exploitation activity in the next 30 days; percentile 26.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary pdfminer.six will execute arbitrary code from a malicious pickle file if provided with a malicious PDF file. The CMapDB.loaddata() function in pdfminer.six uses pickle.loads() to deserialize pickle files. These pickle files are supposed to be part of the pdfminer.six distribution stored in the cmap/ directory, but a malicious PDF can specify an alternative directory and filename as long as the filename ends in .pickle.gz. A malicious, zipped pickle file can then contain code which will automatically execute when the PDF is processed. Details An attacker can: 1. Create a malicious PDF with a CMap reference like /malicious 2. Place a malicious pickle file at /malicious.pickle.gz 3. When the PDF is processed, pdfminer loads and deserializes the malicious pickle 4. The pickle deserialization can execute arbitrary Python code POC Malicious PDF Create a PDF with a malicious CMAP entry: Here the /Encoding points to /pdfs/malicious. Pdfminer will append the extension .pickle.gz to…

Published by the source

7 Nov 2025, 20:52 UTC

Last modified by the source

7 Jul 2026, 17:56 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wf5f-4jwr-ppcp

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wf5f-4jwr-ppcp

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# Patch Next advisory brief: CVE-2025-64512

Advisory: Arbitrary Code Execution in pdfminer.six via Crafted PDF Input
IDs: CVE-2025-64512, GHSA-wf5f-4jwr-ppcp
Record: https://patchnext.com/advisories/cve-2025-64512 (revision 2, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pdfminer-six 20251107. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pdfminer-six: affected < 20251107; fixed in 20251107

## Suggested inspection (read-only)
- `python -m pip show pdfminer-six`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pdfminer-six.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-wf5f-4jwr-ppcp (OSV record GHSA-wf5f-4jwr-ppcp lists affected ranges: PyPI pdfminer-six >=0 <20251107 (fixed))
- Verified: https://github.com/advisories/GHSA-wf5f-4jwr-ppcp (GitHub-reviewed advisory GHSA-wf5f-4jwr-ppcp lists affected ranges: PyPI pdfminer-six >=0 <20251107)

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