CVE-2021-37621Public exploit

Processing hang via zero-length ICC directory traversal

Published Aug 9, 2021 · Updated Aug 4, 2024

Infinite loop in Exiv2 0.27.4 and earlier allows attackers to hang metadata processing through a crafted image's ICC profile. Image::printIFDStructure accepts a zero directory length and continues traversing because its repeated-location guard cannot terminate that case. Triggering requires a victim to print the crafted file's ICC profile with the nondefault -p C option, leaving the processing task hung.

CVSS severity5.5
Medium
EPSS probability1.10%
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 Exiv2 0.27.4 and earlier allows attackers to hang metadata processing through a crafted image's ICC profile. Image::printIFDStructure accepts a zero directory length and continues traversing because its repeated-location guard cannot terminate that case. Triggering requires a victim to print the crafted file's ICC profile with the nondefault -p C option, leaving the processing task hung.

The record

CVE
CVE-2021-37621
Published
Aug 9, 2021
Updated
Aug 4, 2024
Vendor
Exiv2
Product
Exiv2
Classifications
CWE-835, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=<= 0.27.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Exiv2 · Exiv2version=<= 0.27.4

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5GitHub, Inc.CVSS: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

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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')
T1204.002User Execution: Malicious File

Public exploit references

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Technologies

Your stack

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Your stack

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