High severity · published Jul 8, 2026
CVE-2026-59937
pypdf: Possible long runtimes for repeated malformed cross-reference entries
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 49% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pypdf · py-pdf
< 6.14.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59937
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59937
Patch
https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae
Issue Tracking
https://github.com/py-pdf/pypdf/pull/3887
Product
https://github.com/py-pdf/pypdf/releases/tag/6.14.0
Patch
https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v
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