Malicious Stream Processing Flaw in pypdf Open-Source Library
CVE-2026-115585

7.1HIGH

Key Information:

Vendor

Py-PDF

Status
PyPDF
Vendor
CVE Published:
23 October 2026

What is CVE-2026-115585?

The pypdf library, a free and open-source PDF manipulation tool in Python, suffers from a vulnerability that arises from incomplete handling of malformed cross-reference entries. This issue could trigger excessive processing times due to repeated PDF stream reloads during recovery attempts, even when a recovery cache is active. This vulnerability affects all versions prior to 6.21.2 and can significantly degrade performance for applications relying on pypdf for PDF processing. Users are advised to upgrade to version 6.21.2, which rectifies this problem.

Affected Version(s)

pypdf < 6.21.2

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-...
x_refsource_CONFIRM
https://github.com/py-pdf/pypdf/pull/4240
x_refsource_MISC
https://github.com/py-pdf/pypdf/commit/68a0e5046cc9e14a6c...
x_refsource_MISC

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.