pypdf has a possible infinite loop when loading circular /Prev entries in cross-reference streams
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file.
Patches
This has been fixed in pypdf==6.7.2.
Workarounds
If users cannot upgrade yet, consider applying the changes from PR #3655.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pypdf | < 6.7.2 | 6.7.2 |
References
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-2rw7-x74f-jg35
- https://nvd.nist.gov/vuln/detail/CVE-2026-27628
- https://github.com/py-pdf/pypdf/issues/3654
- https://github.com/py-pdf/pypdf/commit/f0a462d36971cf077d74492a348d0d06fd60ea4d
- https://github.com/py-pdf/pypdf
- https://pypi.org/project/pypdf
- https://github.com/advisories/GHSA-2rw7-x74f-jg35
- CVSS 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- Weakness (CWE)
CWE-835- Platform
- Python (PyPI)
- Package
pypdf- Disclosed
- 25.02.2026
- Updated
- 11.10.2026 14:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3005 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-2rw7-x74f-jg35 - CC BY 4.0
Vulnerability history: pypdf
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 51
- First → latest
- 06.2023 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 10
- Medium 38
- Low 3
Disclosures per year
- 2023: 2
- 2024: 0
- 2025: 4
- 2026: 45
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