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Vulnerability · Published Oct 21, 2026 · Assigned by GitHub_M

CVE-2026-113793pypdf: Possible infinite loop when removing tree items

Medium 6.0

In plain English

A medium-severity infinite loop 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 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.0Medium
Exploit odds (30 days)0.4%top 70.8% 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 6.20.1, removing an object from a crafted cyclic PDF tree, such as an outline item, can enter an infinite loop and block the current process. This issue is fixed in version 6.20.1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-113793
Debian:13pypdfno fix listedDEBIAN-CVE-2026-113793
Debian:14pypdf6.21.0-1DEBIAN-CVE-2026-113793
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-113793
PyPIpypdf6.20.1GHSA-9mx8-4j7g-633p
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-113793
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-113793
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-113793
Ubuntu:22.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-113793
Ubuntu:24.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-113793

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.20.1

Weakness: CWE-835 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References