KEVIntel

Vulnerability report

Exploited in the wild High confidence Not in CISA KEV

CVE-2021-33564

Dragonfly

markevans / Dragonfly

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Severity
CVSS 9.8 · Critical
Confidence
High
Exploit status
Exploited in the wild
EPSS
72.2%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-33564 is an unauthenticated vulnerability affecting markevans Dragonfly. An argument injection vulnerability in the Dragonfly gem before 1.4.0 for Ruby allows remote attackers to read and write to arbitrary...

Is it exploited?

Yes. KEVIntel tracks this CVE as a known exploited vulnerability. Confidence is high.

Who is affected?

markevans / Dragonfly.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Dragonfly

An argument injection vulnerability in the Dragonfly gem before 1.4.0 for Ruby allows remote attackers to read and write to arbitrary files via a crafted URL when the verify_url option is disabled. This may lead to code execution.

The problem occurs because the generate and process features mishandle use of the ImageMagick convert utility.

Published
29 May 2021
Exploitation Reported
08 Jul 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why KEVIntel marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 08 Jul 2026

Independent exploitation attestation added to the KEVIntel record.

Proof of concept available

GitHub

Recorded 25 May 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.

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Source Added
The Shadowserver First 2025-07-01 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEVIntel virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-33564.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

72.2%

Weaknesses

Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') CWE-88

All CVSS Scores

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 6.8 Medium

AV:N/AC:M/Au:N/C:P/I:P/A:P

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

mlr0p/CVE-2021-33564

github · Created 2021-05-25 02:48:08 UTC · 16 stars

Argument Injection in Dragonfly Ruby Gem

Ruby Dragonfly <1.4.0 - Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. Added to KEVIntel KEV Feed

    High-confidence, third-party attested exploitation

  2. Nuclei template available

    Scanner coverage available

  3. CVE published

    Vulnerability disclosed publicly

  4. Public PoC available

    Public proof-of-concept code published

  5. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-33564

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-33564",
  "confidence": "High",
  "cvss_score": 9.8,
  "epss_score": 0.72249,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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