Memory Consumption Vulnerability in pypdf Library by Py-PDF
CVE-2026-119209

7.1HIGH

Key Information:

Vendor

Py-PDF

Status
PyPDF
Vendor
CVE Published:
29 October 2026

What is CVE-2026-119209?

The pypdf library, a popular open-source pure-Python PDF processing tool, is susceptible to a memory consumption vulnerability when handling specially crafted PDF files. This issue arises from the ability of PDF documents to contain cross-reference streams that declare unusually large entry counts. Such crafted documents can significantly increase memory use due to highly compressible streams and complex /Prev chains that amplify the number of entries processed. Additionally, negative /Index counts may allow certain documents to bypass existing safeguards within the library's per-stream clamp, leading to potential denial-of-service conditions or significant resource depletion. This vulnerability has been addressed in version 6.21.3 of the library.

Affected Version(s)

pypdf < 6.21.3

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-...
x_refsource_CONFIRM
https://github.com/py-pdf/pypdf/pull/4269
x_refsource_MISC
https://github.com/py-pdf/pypdf/commit/a93fe3a901fd00af38...
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

.