Fluid Attacks Database

Description

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

Impact

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a partially malformed /FlateDecode stream, where the byte-by-byte decompression is used.

Patches

This has been fixed in pypdf==6.18.1.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #4073.

Mitigation

Update Impact

Minimal update. May introduce new vulnerabilities or breaking changes.

Ecosystem	Component	Affected version	Patched versions
pypi	pypdf	>=0 <6.18.1	6.18.1
debian 13	pypdf	=5.4.0-1 \|\| =6.19.0-1 \|\| =6.9.0-1 \|\| =6.9.2-1 \|\| =6.9.2-2	-
debian 12	pypdf2	=2.12.1-3 \|\| =2.12.1-3+deb12u1 \|\| =2.12.1-4	-
debian 12	pypdf	=3.17.4-1 \|\| =3.4.1-1 \|\| =3.4.1-1+deb12u1 \|\| =4.0.0-1 \|\| =4.0.0-1~exp1 \|\| =4.0.1-1 \|\| =4.0.2-1 \|\| =4.1.0-1 \|\| =4.2.0-1 \|\| =4.3.1-1 \|\| =5.4.0-1 \|\| =6.19.0-1 \|\| =6.9.0-1 \|\| =6.9.2-1 \|\| =6.9.2-2	-
debian 14	pypdf	=5.4.0-1 \|\| =6.9.0-1 \|\| =6.9.2-1 \|\| =6.9.2-2 \|\| >=0 <6.19.0-1	6.19.0-1

Aliases

1. CVE-2026-1029972. NVD-2026-1029973. OSV-2026-1029974. OSV-DEBIAN-2026-1029975. GHSA-jw7q-gvrg-4vj36. GCVE-2026-1029977. SECURITY-TRACKER-CVE-2026-102997

References

1. https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj32. https://github.com/py-pdf/pypdf/pull/40733. https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f794. https://github.com/py-pdf/pypdf/releases/tag/6.18.1

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