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Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

CVE-2026-59937pypdf: Possible long runtimes for repeated malformed cross-reference entries

Medium 6.9

In plain English

A medium-severity uncontrolled resource consumption in pypdf from py-pdf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.9Medium
Exploit odds (30 days)0.6%top 50.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-59937
Debian:13pypdfno fix listedDEBIAN-CVE-2026-59937
Debian:14pypdf6.19.0-1DEBIAN-CVE-2026-59937
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-59937
PyPIpypdf6.14.0GHSA-55h5-xmcq-c37v
PyPIpypdf6.14.0PYSEC-2026-3610
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-59937
Ubuntu:25.10pypdfno fix listedUBUNTU-CVE-2026-59937
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-59937
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-59937
Ubuntu:22.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-59937
Ubuntu:24.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-59937

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.14.0

Weakness: CWE-400 · 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

References