GHSA-jw7q-gvrg-4vj3

pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)

Source: GitHub Advisory Database (reviewed) High CVE-2026-102997

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	pypdf	< 6.18.1	6.18.1

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 long runtimes. This requires a partially malformed `/FlateDecode` stream, where the byte-by-byte decompression is used. ### Patches This has been fixed in [pypdf==6.18.1](https://github.com/py-pdf/pypdf/releases/tag/6.18.1). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4073](https://github.com/py-pdf/pypdf/pull/4073).

References

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

https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj3 web
https://nvd.nist.gov/vuln/detail/CVE-2026-102997 advisory
https://github.com/py-pdf/pypdf/pull/4073 web
https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f79 web
https://github.com/py-pdf/pypdf package
https://github.com/py-pdf/pypdf/releases/tag/6.18.1 web