Medium [CVE-2026-84309] Denial of Service via crafted PDF with cyclic tree structure
This medium-severity Red Hat Linux advisory covers CVE-2026-84309 affecting Exploit Intelligence, Lightspeed Core, OpenShift Lightspeed.
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Summary
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. A flaw was found in pypdf.
This can result in a denial of service (DoS) due to resource exhaustion. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).
Weakness: CWE-835. Affected Red Hat products: Exploit Intelligence; Lightspeed Core; OpenShift Lightspeed; Red Hat Ansible Automation Platform 2; Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift AI (RHOAI); Red Hat Quay 3.
Will not fix / out of support: Exploit Intelligence; Red Hat Ansible Automation Platform 2; Red Hat Quay 3. Red Hat does not currently list a fixing RHSA for this CVE.
- < 6.16.0
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation
Upgrade to a fixed release: 6.16.0. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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