CVE-2026-113791

Medium

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF containing a content stream with many small operations, causing parsing to consume large amounts of memory. This issue is fixed in version 6.21.0.

SeverityMedium

CVSS6.0

Exploit probability—

ProductPypdf

PublishedOct 21, 2026

First seenOct 21, 2026

Weakness typeCWE-400Uncontrolled resource consumption CWE-770Allocation of resources without limits

How to fix

Update

pypdf6.21.0 or later
py-pdf pypdf6.21.0 or later

Patches

github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
github.com/py-pdf/pypdf/pull/4218
github.com/py-pdf/pypdf/security/advisories/GHSA-cgf9-327m-v77c

Vendor advisories

github.com/py-pdf/pypdf/releases/tag/6.21.0

Affected products

Product	Affected versions	Fixed in
pypdfPyPI	v < 6.21.0	6.21.0
py-pdf pypdf	v < 6.21.0	6.21.0

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

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