pypdf: Possible long runtimes/large memory usage when extracting XForm objects

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-84311
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-01 21:18:46 UTC
Updated2026-09-02 16:17:28 UTC
Descriptionpypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.

Risk And Classification

Primary CVSS: v4.0 4.8 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.001380000 probability, percentile 0.034770000 (date 2026-09-02)

Problem Types: CWE-834 | CWE-834 CWE-834: Excessive Iteration

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary4.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED4.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Confidentiality
None
Integrity
None
Availability
Low
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Py-pdf Pypdf affected < 6.16.1 Not specified

References

ReferenceSourceLinkTags
github.com/py-pdf/pypdf/security/advisories/GHSA-763m-79hh-57f2 [email protected] github.com
github.com/py-pdf/pypdf/releases/tag/6.16.1 [email protected] github.com
github.com/py-pdf/pypdf/pull/3966 [email protected] github.com
github.com/py-pdf/pypdf/commit/d91ab705fd81ed1a9cec175c6958600dea1a4942 [email protected] github.com
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