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Vulnerability record · CVE-2026-82398 · published 31 August 2026

CVE-2026-82398: Pypdf project pypdf vulnerability

PPypdf Project · Pypdf

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

6.9 CVSS 4.0 Medium EPSS 0.52% · top 57.4% CWE-407 · CWE-407
6.9CVSS 4.0 base score
0.52%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
5 Oct 2026Last modified by NVD

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa Patch
https://github.com/py-pdf/pypdf/pull/3947 Patch
https://github.com/py-pdf/pypdf/releases/tag/6.15.0 Release Notes
https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m PatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-82398), CISA KEV, FIRST EPSS (scores of 2026-10-08). This page is refreshed as NVD updates the record.