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OpenAdvisories
High · 8.7 CVE-2026-102997 EUVD-2026-90373GHSA-jw7q-gvrg-4vj3PYSEC-2026-4156

pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)

Published Sep 30, 2026 · Updated Oct 2, 2026 · Assigned by GitHub_M

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.

Affected products

VendorProductAffectedFixed
py-pdf pypdf < 6.18.1 —

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 —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling open-webui 0.11.4-r3 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI pypdf < 6.18.1 6.18.1 GHSA-jw7q-gvrg-4vj3

References