What’s Vulnerable › Vulnerabilities

CVE-2026-113793: pypdf: Possible infinite loop when removing tree items

• Severity: medium (CVSS 6.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-28
• Weakness: CWE-835

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.20.1, removing an object from a crafted cyclic PDF tree, such as an outline item, can enter an infinite loop and block the current process. This issue is fixed in version 6.20.1.

Affected products

• py-pdf pypdf: before 6.20.1

References

• https://github.com/py-pdf/pypdf/commit/c9c35b4471c2eb5fe078094f6c816e69d4ed25a0
• https://github.com/py-pdf/pypdf/pull/4188
• https://github.com/py-pdf/pypdf/releases/tag/6.20.1
• https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mx8-4j7g-633p

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