CVE-2026-84310

pypdf: Possible long runtimes/large memory usage when retrieving outlines

LOW
3.3
CVSS Score
Published: September 1, 2026 at 08:00 PM UTC
Updated: October 5, 2026 at 05:42 PM UTC
2 products affected across 2 vendorsPypdfPypdf

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Severity
LOW3.3
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_doc_common.py _get_outline to consume long runtimes and large amounts of memory when retrieving document outlines with large numbers of entries or deeply nested reused paths because the traversal lacked global entry-count and nesting-depth limits. This issue is fixed in version 6.16.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.16.1
Affected range stops below 6.16.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/py-pdf/pypdf/security/advisories/GHSA-23w6-3w8w-8484
x_refsource_MISCPatch
Source: cverecord
https://github.com/py-pdf/pypdf/pull/3966
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/py-pdf/pypdf/releases/tag/6.16.1

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-405CWE-834

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