What’s Vulnerable › Vulnerabilities

CVE-2026-113791: pypdf: Possible large memory usage when parsing content streams

• Severity: medium (CVSS 6.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-30
• Weakness: CWE-400

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.

Affected products

• py-pdf pypdf: before 6.21.0

References

• https://github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
• https://github.com/py-pdf/pypdf/pull/4218
• https://github.com/py-pdf/pypdf/releases/tag/6.21.0
• https://github.com/py-pdf/pypdf/security/advisories/GHSA-cgf9-327m-v77c

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