CVE-2021-33564
High PUBLISHEDAn 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...
Not yet in CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- May 29, 2021
- Exploitation Reported
- Jul 08, 2026
- CVSS
- 9.8 Critical
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| n/a |
n/a
|
n/a |
Affected |
CVE References
- GitHub — markevans/dragonfly github.com · CVE Record https://github.com/markevans/dragonfly/issues/513
- GitHub — markevans/dragonfly github.com · CVE Record https://github.com/markevans/dragonfly/commit/25399297bb457f7fcf8e3f9...
- GitHub — markevans/dragonfly github.com · CVE Record https://github.com/markevans/dragonfly/compare/v1.3.0...v1.4.0
- raw.githubusercontent.com/projectdiscovery/nuclei-templates/master/cve... raw.githubusercontent.com · CVE Record https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/m...
- GitHub — mlr0p/CVE-2021-33564 github.com · CVE Record https://github.com/mlr0p/CVE-2021-33564
Show 1 more reference
- zxsecurity.co.nz/research/argunment-injection-ruby-dragonfly zxsecurity.co.nz · CVE Record https://zxsecurity.co.nz/research/argunment-injection-ruby-dragonfly/
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2025-07-01 00:00 UTC |
Scanner Artifacts
Nuclei and Metasploit references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-33564.yaml | Apr 25, 2025 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV:N/AC:M/Au:N/C:P/I:P/A:P
Exploitation Status
Exploited in the wild
Recorded 2026-07-08 00:00:00 UTC · The Shadowserver
Proof of concept available
Recorded 2021-05-25 02:48:08 UTC · GitHub
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-33564.yaml | Apr 25, 2025 |
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2021-05-25 02:48:08 UTC · 16 stars
Argument Injection in Dragonfly Ruby Gem
nuclei · Created Unknown
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
00:00 UTC about 1 year ago00:00 UTC · about 1 year ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
00:00 UTC about 1 year ago00:00 UTC · about 1 year ago
Nuclei template available
Scanner coverage available
-
13:19 UTC about 5 years ago13:19 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
02:48 UTC about 5 years ago02:48 UTC · about 5 years ago
Public PoC available
Public proof-of-concept code published
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-33564
{
"cve_id": "CVE-2021-33564",
"title": "An argument injection vulnerability in the Dragonfly gem before 1.4.0 for Rub...",
"affected_vendor": "markevans",
"affected_product": "Dragonfly",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "High",
"cvss_score": 9.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}