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OpenAdvisories
Medium · 6.9 CVE-2026-82398 EUVD-2026-68894GHSA-fc8x-2rww-xw9mPYSEC-2026-3912

pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

Published Aug 31, 2026 · Updated Sep 1, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
py-pdf pypdf < 6.15.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 pypdf 6.19.0-1 —
Debian 13 pypdf No fix yet —
Debian 12 pypdf +1 No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 pypdf No fix yet —
Ubuntu 26.04 LTS pypdf No fix yet —
Ubuntu 24.04 LTS pypdf +1 No fix yet —
Ubuntu 22.04 LTS pypdf2 No fix yet —
Ubuntu 20.04 LTS pypdf2 No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 18.04 LTS pypdf2 No fix yet —
Ubuntu Pro 16.04 LTS pypdf2 No fix yet —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI pypdf < 6.15.0 6.15.0 GHSA-fc8x-2rww-xw9m

References