CVE-2026-27026 — Allocation of Resources Without Limits or Throttling in Pypdf

CWE-770 — Allocation of Resources Without Limits or ThrottlingCWE-1050 — Excessive Platform Resource Consumption within a Loop7 documents6 sources
Severity
6.9MEDIUMNVD
EPSS
0.0%
top 99.76%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Py-pdf PypdfPypdf Project PypdfDebian Pypdf+1 more
Timeline
PublishedFeb 20

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Affected Packages6 packages

▶CVEListV5py-pdf/pypdf< 6.7.1
▶debiandebian/pypdf< pypdf 6.9.0-1 (forky)
▶debiandebian/pypdf2< pypdf 6.9.0-1 (forky)
▶NVDpypdf_project/pypdf< 6.7.1
▶PyPIpypdf_project/pypdf< 6.7.1

Patches

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

🔴Vulnerability Details

3
OSV
CVE-2026-27026: pypdf is a free and open-source pure-python PDF library↗2026-02-20
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OSV
pypdf possibly has long runtimes for malformed FlateDecode streams↗2026-02-18
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GHSA
pypdf possibly has long runtimes for malformed FlateDecode streams↗2026-02-18
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📋Vendor Advisories

2
Red Hat
pypdf: pypdf: Denial of Service via malformed PDF /FlateDecode stream↗2026-02-20
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Debian
CVE-2026-27026: pypdf - pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an atta...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-27026 Impact, Exploitability, and Mitigation Steps | Wiz↗
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