CVE-2026-24688

MEDIUM

pypdf < 6.6.2 - Denial of Service via Infinite Loop in Outline Processing

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 3 public exploits for CVE-2026-24688. PoCs published by SecureWithUmer, Fomovet, JoakimBulow.

AI-analyzed exploit summary This repository contains a functional proof-of-concept for CVE-2026-24688, a denial-of-service vulnerability in pypdf's outline parsing logic. The exploit creates PDFs with circular outline references that trigger infinite loops and memory exhaustion when processed by vulnerable versions of pypdf (6.6.0).

Description

pypdf is a free and open-source pure-python PDF library. An attacker who uses an infinite loop vulnerability that is present in versions prior to 6.6.2 can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. This has been fixed in pypdf 6.6.2. If projects cannot upgrade yet, consider applying the changes from PR #3610 manually.

Exploits (3)

github WORKING POC
by SecureWithUmer · c++poc
https://github.com/SecureWithUmer/CVE-2026-PoCs/tree/main/2026/CVE-2026-24688

This repository contains a functional proof-of-concept for CVE-2026-24688, a denial-of-service vulnerability in pypdf's outline parsing logic. The exploit creates PDFs with circular outline references that trigger infinite loops and memory exhaustion when processed by vulnerable versions of pypdf (6.6.0).

Classification
Working Poc 99%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: pypdf version 6.6.0
No auth needed
Prerequisites: Target must use vulnerable version of pypdf (6.6.0) · Target must process the malicious PDF (e.g., via PdfReader.outline)
mistral-large-3 · analyzed Jul 08, 2026 Full analysis →
github WORKING POC
by Fomovet · pythonpoc
https://github.com/Fomovet/cve-2026-24688

This repository contains a functional exploit PoC for CVE-2026-24688, demonstrating a DoS vulnerability in pypdf's outline parsing logic via circular references. The exploit generates malicious PDFs that trigger infinite loops, causing CPU spikes and memory exhaustion.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: pypdf (versions before 6.6.2)
No auth needed
Prerequisites: pypdf (vulnerable version 6.6.0)
mistral-large-3 · analyzed Jun 21, 2026 Full analysis →
nomisec WORKING POC
by JoakimBulow · poc
https://github.com/JoakimBulow/CVE-2026-24688

This repository contains a working proof-of-concept for CVE-2026-24688, a critical Denial of Service (DoS) vulnerability in pypdf's outline parsing logic. The exploit demonstrates how circular references in PDF outlines cause an infinite loop, leading to system-wide crashes due to uncontrolled memory allocation.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: pypdf version 6.6.0
No auth needed
Prerequisites: Python environment with pypdf==6.6.0 installed
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 4.3
EPSS 0.0039
EPSS Percentile 31.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-835
Status published
Products (2)
pypdf_project/pypdf < 6.6.2
pypi/pypdf 0 - 6.6.2PyPI
Published Jan 27, 2026
Tracked Since Feb 18, 2026