CVE-2026-24688Public exploit

Application hang via cyclic outline references

Published Jan 27, 2026 · Updated Jan 27, 2026

Infinite loop in pypdf before 6.6.2 allows attackers to hang PDF-processing applications through a crafted document. The _get_outline method follows cyclic /Next and /First outline references without tracking visited nodes, repeatedly appending outline objects instead of reaching its loop exit. Exploitation requires a consuming application to open the document and access its outlines or bookmarks, after which CPU and memory consumption can interrupt that application.

CVSS severity5.1
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in pypdf before 6.6.2 allows attackers to hang PDF-processing applications through a crafted document. The _get_outline method follows cyclic /Next and /First outline references without tracking visited nodes, repeatedly appending outline objects instead of reaching its loop exit. Exploitation requires a consuming application to open the document and access its outlines or bookmarks, after which CPU and memory consumption can interrupt that application.

The record

CVE
CVE-2026-24688
Published
Jan 27, 2026
Updated
Jan 27, 2026
Vendor
py-pdf
Product
pypdf
Classifications
CWE-835, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.6.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

py-pdf · pypdfversion=< 6.6.2

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
5.1GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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