CVE-2026-119209: py-pdf pypdf

CVSS 7.1 (high) · published 2026-10-29

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive memory while opening a crafted PDF containing cross-reference streams that declare very large entry counts. Highly compressible streams and /Prev chains can multiply the number of parsed entries across a document, while negative /Index counts can bypass the existing per-stream clamp. This issue is fixed in version 6.21.3.

Affected products (NVD): py-pdf pypdf

Fixed in (NVD): 6.21.3

Weakness: CWE-400, CWE-770

Source: NVD CVE-2026-119209

References

• https://github.com/py-pdf/pypdf/commit/a93fe3a901fd00af38f0a105c3ba7175fa72dcb4
• https://github.com/py-pdf/pypdf/pull/4269
• https://github.com/py-pdf/pypdf/releases/tag/6.21.3
• https://github.com/py-pdf/pypdf/security/advisories/GHSA-x3rh-gjgm-fmqc

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