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Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M

CVE-2026-27628pypdf has a possible infinite loop when loading circular /Prev entries in cross-reference streams

Low 1.2

In plain English

A low-severity infinite loop in pypdf from py-pdf. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)1.2Low
Exploit odds (30 days)0.4%top 65.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.2, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. This has been fixed in pypdf 6.7.2. As a workaround, one may apply the patch manually.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pypdfno fix listedDEBIAN-CVE-2026-27628
Debian:13pypdfno fix listedDEBIAN-CVE-2026-27628
Debian:14pypdf6.9.0-1DEBIAN-CVE-2026-27628
Debian:12pypdf2no fix listedDEBIAN-CVE-2026-27628
PyPIpypdf6.7.2GHSA-2rw7-x74f-jg35
PyPIpypdf6.7.2PYSEC-2026-3005
Ubuntu:24.04:LTSpypdfno fix listedUBUNTU-CVE-2026-27628
Ubuntu:25.10pypdfno fix listedUBUNTU-CVE-2026-27628
Ubuntu:26.04:LTSpypdfno fix listedUBUNTU-CVE-2026-27628
Ubuntu:26.10pypdfno fix listedUBUNTU-CVE-2026-27628
Ubuntu:22.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-27628
Ubuntu:24.04:LTSpypdf2no fix listedUBUNTU-CVE-2026-27628

Affected products (as reported)

VendorProductVersions
py-pdf pypdf < 6.7.2

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

References