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PYSEC-2026-1831

pypdf can exhaust RAM via manipulated LZWDecode streams

Quick fix

PYSEC-2026-1831 — pypdf: upgrade to the fixed version with the command below.

pip install --upgrade 'pypdf>=6.1.3'

Details

### Impact

An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream of a page using the LZWDecode filter.

### Patches This has been fixed in [pypdf==6.1.3](https://github.com/py-pdf/pypdf/releases/tag/6.1.3).

### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3502](https://github.com/py-pdf/pypdf/pull/3502).

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI/pypdf

Introduced in: 0Fixed in: 6.1.3

Fixpip install --upgrade 'pypdf>=6.1.3'

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-jfx9-29x2-rv3j[WEB]
https://nvd.nist.gov/vuln/detail/CVE-2025-62708[ADVISORY]
https://github.com/py-pdf/pypdf/pull/3502[WEB]
https://github.com/py-pdf/pypdf/commit/e51d07807ffcdaf18077b9486dadb3dc05b368da[WEB]
https://github.com/py-pdf/pypdf[PACKAGE]
https://github.com/py-pdf/pypdf/releases/tag/6.1.3[WEB]
https://pypi.org/project/pypdf[PACKAGE]
https://github.com/advisories/GHSA-jfx9-29x2-rv3j[ADVISORY]