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Actively exploited

CVE-2021-22204 ExifTool Remote Code Execution Vulnerability

Improper neutralization of user data in the DjVu file format in Exiftool versions 7.44 and up allows arbitrary code execution when parsing the malicious image

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 17 Nov 2021.
  • Rated Medium severity (CVSS 6.8, scored by Vendor).
  • It has been in the catalogue for 1,815 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Improper neutralization of user data in the DjVu file format in ExifTool versions 7.44 and up allows arbitrary code execution when parsing the malicious image

Affected Versions

ProductVersions
ExifTool ExifTool>=7.44, <12.24

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Perl Exiftool. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsCyber Essentials requires high and critical updates (CVSS 7.0 or above) within 14 days of release. Treat any exploited flaw the same way.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 1 Dec 2021 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2021-22204
  3. CVE record: CVE-2021-22204
  4. FIRST EPSS
  5. github.com/exiftool/exiftool/commit/cf0f4e7dcd024ca99615bfd1102a841a25dde031#diff-fa0d652d10dbcd246e
  6. hackerone.com/reports/1154542
  7. gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22204.json
  8. debian.org/security/2021/dsa-4910
  9. lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U4RF6PJCJ6N
  10. lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DDKDLJLBTBB
  11. lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F6UOBPU3LSH
  12. openwall.com/lists/oss-security/2021/05/09/1