CVE-2026-22690
pypdf has possible long runtimes for missing /Root object with large /Size values
Impact
### Impact An attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for actually invalid files. This can be achieved by omitting the `/Root` entry in the trailer, while using a rather large `/Size` value. Only the non-strict reading mode is affected. ### Patches This has been fixed in [pypdf==6.6.0](https://github.com/py-pdf/pypdf/releases/tag/6.6.0). ### Workarounds ```python from pypdf import PdfReader, PdfWriter # Instead of reader = PdfReader("file.pdf") # use the strict mode: reader = PdfReader("file.pdf", strict=True) # Instead of writer = PdfWriter(clone_from="file.pdf") # use an explicit strict reader: writer = PdfWriter(clone_from=PdfReader("file.pdf", strict=True)) ``` ### Resources This issue has been fixed in #3594.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pypdf | < 6.6.0 | 6.6.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pypdf Project | Pypdf | before 6.6.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45
- https://github.com/py-pdf/pypdf/pull/3594
- https://github.com/py-pdf/pypdf/releases/tag/6.6.0
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-4xc4-762w-m6cg
- https://github.com/advisories/GHSA-4xc4-762w-m6cg
- https://nvd.nist.gov/vuln/detail/CVE-2026-22690