GHSA-9m86-7pmv-2852

pypdf vulnerable to inefficient decoding of ASCIIHexDecode streams

Source: GitHub Advisory Database (reviewed) Moderate CVE-2026-28804

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	pypdf	< 6.7.5	6.7.5

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 accessing a stream which uses the `/ASCIIHexDecode` filter. ### Patches This has been fixed in [pypdf==6.7.5](https://github.com/py-pdf/pypdf/releases/tag/6.7.5). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3666](https://github.com/py-pdf/pypdf/pull/3666).

References

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

https://github.com/py-pdf/pypdf/security/advisories/GHSA-9m86-7pmv-2852 web
https://nvd.nist.gov/vuln/detail/CVE-2026-28804 advisory
https://github.com/py-pdf/pypdf/pull/3666 web
https://github.com/py-pdf/pypdf/commit/648c627d2657447dfb1773412af05a0a5103b98f web
https://github.com/py-pdf/pypdf package
https://github.com/py-pdf/pypdf/releases/tag/6.7.5 web