pypdf possibly has long runtimes for malformed FlateDecode streams
### Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed `/FlateDecode` stream, where the byte-by-byte decompression is used. ### Patches This has been fixed in [pypdf==6.7.1](https://github.com/py-pdf/pypdf/releases/tag/6.7.1). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3644](https://github.com/py-pdf/pypdf/pull/3644).
01
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-27026US | medium5.5 | — | ||
pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malfo… | ||||
02
references
External citations — patches, advisories, analysis.
- https://github.com/py-pdf/pypdfPACKAGE
- https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016WEB
- https://github.com/py-pdf/pypdf/pull/3644WEB
- https://github.com/py-pdf/pypdf/releases/tag/6.7.1WEB
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8hWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-27026ADVISORY
scry
Advisories like this name the exposed products attackers go after on your perimeter. See what is exposed on your perimeter with a free passive scan.
Free scan