CVE-2021-20312Network attack vector

System availability loss via thumbnail integer overflow

Published May 11, 2021 · Updated Aug 3, 2024

Integer overflow in ImageMagick 7.0.11 allows remote attackers to interrupt service via crafted image files processed by applications. WriteTHUMBNAILImage in coders/thumbnail.c performs unchecked arithmetic on thumbnail dimensions, triggering undefined behavior during image output. Exploitation requires an application to process an attacker-supplied image; the documented consequence is service availability loss without reported confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability2.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in ImageMagick 7.0.11 allows remote attackers to interrupt service via crafted image files processed by applications. WriteTHUMBNAILImage in coders/thumbnail.c performs unchecked arithmetic on thumbnail dimensions, triggering undefined behavior during image output. Exploitation requires an application to process an attacker-supplied image; the documented consequence is service availability loss without reported confidentiality or integrity impact.

The record

CVE
CVE-2021-20312
Published
May 11, 2021
Updated
Aug 3, 2024
Vendor
ImageMagick Studio LLC
Product
ImageMagick
Classifications
CWE-190, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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

  1. Affected versionversion=ImageMagick 7.0.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ImageMagick Studio LLC · ImageMagickversion=ImageMagick 7.0.11

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8NVDAV:N/AC:L/Au:N/C:N/I:N/A:C

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

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499Endpoint Denial of Service

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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