What’s Vulnerable › Vulnerabilities

CVE-2026-102996: pypdf: Possible large memory usage when parsing font data

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-30 · updated 2026-10-05
• Weakness: CWE-400

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF can provide a TrueType or Type1 simple font with an unusually large /Widths array, causing pypdf/_font.py Font._collect_tt_t1_character_widths to process entries beyond the 256 character codes meaningful for a simple font and consume excessive memory during operations such as text extraction. This issue is fixed in version 6.18.1.

Affected products

• py-pdf pypdf: before 6.18.1 — fixed in 6.18.1

How to fix

Upgrade to a fixed version: py-pdf pypdf 6.18.1. Check the vendor advisory for mitigations.

References

• https://github.com/py-pdf/pypdf/commit/0fb26eb8cdd01c44b3b2c9fe8329751be2f7cfd5
• https://github.com/py-pdf/pypdf/pull/4072
• https://github.com/py-pdf/pypdf/releases/tag/6.18.1
• https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9cg-prrw-2r8q

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