CVE-2026-22691 — Uncontrolled Resource Consumption in Pypdf

CWE-400 — Uncontrolled Resource ConsumptionCWE-1333 — Regex Denial of ServiceCWE-1050 — Excessive Platform Resource Consumption within a Loop7 documents6 sources
Severity
2.7LOWNVD
EPSS
0.0%
top 94.67%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Py-pdf PypdfPypdf Project PypdfDebian Pypdf+1 more
Timeline
PublishedJan 10

Description

pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in versi…

CVSS vector

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

Affected Packages6 packages

▶CVEListV5py-pdf/pypdf< 6.6.0
▶debiandebian/pypdf< pypdf 6.9.0-1 (forky)
▶debiandebian/pypdf2< pypdf 6.9.0-1 (forky)
▶NVDpypdf_project/pypdf< 6.6.0
▶PyPIpypdf_project/pypdf< 6.6.0

Patches

Patch: github.com ↗Patch: github.com ↗

🔴Vulnerability Details

3
OSV
CVE-2026-22691: pypdf is a free and open-source pure-python PDF library↗2026-01-10
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OSV
pypdf has possible long runtimes for malformed startxref↗2026-01-09
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GHSA
pypdf has possible long runtimes for malformed startxref↗2026-01-09
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📋Vendor Advisories

2
Red Hat
pypdf: pypdf: Denial of Service via malformed PDF startxref entries↗2026-01-10
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Debian
CVE-2026-22691: pypdf - pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0,...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-22691 Impact, Exploitability, and Mitigation Steps | Wiz↗
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