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CVE-2026-48156

pypdf: Possible long runtimes for zero-only width values in cross-reference streams

Published: May 28, 2026Updated: May 29, 2026 Sources: CVE List NVDCWE-834
NVD MITRE
3.3CVSSLOW
EPSS Score
0.1%
Top 97.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

CVSS Vector Breakdown

AV:LAC:LPR:NUI:RS:UC:NI:NA:L
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-834

Affected Products

pypdfpy-pdf
On-prem
OSS Libraries / pypi
pypdfpypdf project
Library
OSS Libraries / generic-library
py-pdfpackage-ecosystemOSS Librariesaka pypdf, pypdf2
pypdf projectoss-projectOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-248m-82v9-q6g6
github.com
https://github.com/py-pdf/pypdf/pull/3791
github.com
https://github.com/py-pdf/pypdf/releases/tag/6.12.0
github.com

Timeline

Published
May 28, 2026
Last Updated
May 29, 2026

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