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PYSEC-2026-3017

pypdf: Manipulated RunLengthDecode streams can exhaust RAM

Quick fix

PYSEC-2026-3017 — pypdf: upgrade to the fixed version with the command below.

pip install --upgrade 'pypdf>=6.7.4'

Details

### Impact

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

### Patches This has been fixed in [pypdf==6.7.4](https://github.com/py-pdf/pypdf/releases/tag/6.7.4).

### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3664](https://github.com/py-pdf/pypdf/pull/3664).

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI/pypdf

Introduced in: 0Fixed in: 6.7.4

Fixpip install --upgrade 'pypdf>=6.7.4'

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-f2v5-7jq9-h8cg[WEB]
https://nvd.nist.gov/vuln/detail/CVE-2026-28351[ADVISORY]
https://github.com/py-pdf/pypdf/pull/3664[WEB]
https://github.com/py-pdf/pypdf/commit/f309c6003746414dc7b5048c19e6d879ff2dc858[WEB]
https://github.com/py-pdf/pypdf[PACKAGE]
https://github.com/py-pdf/pypdf/releases/tag/6.7.4[WEB]
https://pypi.org/project/pypdf[PACKAGE]
https://github.com/advisories/GHSA-f2v5-7jq9-h8cg[ADVISORY]