pypdf: Possible infinite loop for TreeObject.insert_child (CVE-2026-84309) | HOL Guard CVE

Medium severityCVE-2026-84309GHSA-JP53-MHQP-8XCG

pypdf: Possible infinite loop for TreeObject.insert_child

Answer in brief

CVE-2026-84309 records a Medium severity vulnerability in pypdf: Possible infinite loop for TreeObject.insert_child. The current sources do not mark it as known exploited. The current feed maps py-pdf/pypdf (generic), pypdf (pip). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 1, 2026Updated Sep 1, 2026Source checked Sep 1, 2026First seen by HOL Sep 1, 2026Material review Sep 1, 2026

Upstream Advisory

Key facts

Risk: Medium
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps py-pdf/pypdf (generic), pypdf (pip). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
py-pdf/pypdfgeneric	< 6.16.0	Not reported
pypdfpip	<6.16.0	6.16.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for py-pdf/pypdf, pypdf.
Review the reported fix. Update pypdf to 6.16.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 1, 2026

Sources and claim methodology

Upstream source description

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.

Quoted source text, attributed separately from HOL analysis.