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Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M

CVE-2026-84311pypdf: Possible long runtimes/large memory usage when extracting XForm objects

Medium 4.8

In plain English

A medium-severity security flaw 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 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)4.8Medium
Exploit odds (30 days)0.1%top 97.0% 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 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-84311
Debian:13pypdfno fix listedDEBIAN-CVE-2026-84311
Debian:14pypdf6.19.0-1DEBIAN-CVE-2026-84311
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-84311
PyPIpypdf6.16.1GHSA-763m-79hh-57f2
PyPIpypdf6.16.1PYSEC-2026-3911
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-84311
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-84311
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-84311
Ubuntu:22.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-84311
Ubuntu:24.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-84311

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.16.1

Weakness: CWE-834 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References