high7.5
CVE-2026-102997
pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
Impact
pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pypdf | < 6.18.1 | 6.18.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pypdf Project | Pypdf | before 6.18.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-jw7q-gvrg-4vj3
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj3
- https://nvd.nist.gov/vuln/detail/CVE-2026-102997
- https://github.com/py-pdf/pypdf/pull/4073
- https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f79
- https://github.com/py-pdf/pypdf/releases/tag/6.18.1