GHSA-g9xf-7f8q-9mcj

pypdf: Possible infinite loop when processing threads/articles in writer

Source: GitHub Advisory Database (reviewed) Moderate CVE-2026-54651

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	pypdf	< 6.13.1	6.13.1

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. ### Patches This has been fixed in [pypdf==6.13.1](https://github.com/py-pdf/pypdf/releases/tag/6.13.1). ### Workarounds If users cannot upgrade yet, consider applying the changes from PR [#3839](https://github.com/py-pdf/pypdf/pull/3839).

References

External links from the advisory. They lead to third-party sites.

https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9xf-7f8q-9mcj web
https://nvd.nist.gov/vuln/detail/CVE-2026-54651 advisory
https://github.com/py-pdf/pypdf/pull/3839 web
https://github.com/py-pdf/pypdf package
https://github.com/py-pdf/pypdf/releases/tag/6.13.1 web