CVE-2023-31794

Tool hang via undetected PDF resource cycles

Published Oct 31, 2023 · Updated Sep 5, 2024

Uncontrolled recursion in MuPDF 1.21.1 allows attackers to hang the mutool info process by supplying a crafted PDF file. Resource traversal fails to mark direct Font, XObject, Shading, and Pattern dictionaries before following legal indirections, while mark-list expansion also discards prior entries. Processing the file requires user interaction and repeatedly revisits the resource cycle, interrupting only the invoking tool.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in MuPDF 1.21.1 allows attackers to hang the mutool info process by supplying a crafted PDF file. Resource traversal fails to mark direct Font, XObject, Shading, and Pattern dictionaries before following legal indirections, while mark-list expansion also discards prior entries. Processing the file requires user interaction and repeatedly revisits the resource cycle, interrupting only the invoking tool.

The record

CVE
CVE-2023-31794
Published
Oct 31, 2023
Updated
Sep 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-674, T1499.004, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
T1499.004Application or System Exploitation
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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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