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Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M

CVE-2026-33699pypdf: Possible infinite loop during recovery attempts in DictionaryObject.read_from_stream

Medium 4.6

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 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)4.6Medium
Exploit odds (30 days)0.5%top 59.0% 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. Versions prior to 6.9.2 have a vulnerability in which an attacker can craft a PDF which leads to an infinite loop. This requires reading a file in non-strict mode. This has been fixed in pypdf 6.9.2. If users cannot upgrade yet, consider applying the changes from the patch manually.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-33699
Debian:13pypdfno fix listedDEBIAN-CVE-2026-33699
Debian:14pypdf6.9.2-1DEBIAN-CVE-2026-33699
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-33699
PyPIpypdf6.9.2GHSA-87mj-5ggw-8qc3
PyPIpypdf6.9.2PYSEC-2026-3012
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-33699
Ubuntu:25.10pypdfno fix listedUBUNTU-CVE-2026-33699
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-33699
Ubuntu:22.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-33699
Ubuntu:24.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-33699

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.9.2

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

References