CVE-2026-33899Network attack vector

Service disruption via XML conversion underflow

Published Apr 13, 2026 · Updated Apr 13, 2026

Heap-based buffer overflow in ImageMagick before 6.9.13-44 and 7.1.2-19 allows remote attackers to disrupt processing via crafted XML. NewXMLTree indexes utf8[length-1] after an empty UTF-8 conversion; when length is zero, the subtraction underflows and a null byte is written before the heap buffer. Reachability requires a consuming application to pass attacker-controlled XML to the parser, and the published impact is limited to service disruption.

CVSS severity5.3
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in ImageMagick before 6.9.13-44 and 7.1.2-19 allows remote attackers to disrupt processing via crafted XML. NewXMLTree indexes utf8[length-1] after an empty UTF-8 conversion; when length is zero, the subtraction underflows and a null byte is written before the heap buffer. Reachability requires a consuming application to pass attacker-controlled XML to the parser, and the published impact is limited to service disruption.

The record

CVE
CVE-2026-33899
Published
Apr 13, 2026
Updated
Apr 13, 2026
Vendor
ImageMagick Studio LLC
Product
ImageMagick
Classifications
CWE-122, CWE-191
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 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=< 6.9.13-44
  2. Affected versionversion=< 7.1.2-19

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ImageMagick Studio LLC · ImageMagickversion=< 6.9.13-44; version=< 7.1.2-19

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-191Integer Underflow (Wrap or Wraparound)

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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