CVE-2021-33564
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 72.1%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 72.14% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-88
- Affected
- dragonfly project/dragonfly
- Source
- cve@mitre.org
EPSS 72.1% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/markevans/dragonfly/commit/25399297bb457f7fcf8e3f91e85945b255b111b5Patch, Third Party Advisory
- https://github.com/markevans/dragonfly/compare/v1.3.0...v1.4.0Patch, Third Party Advisory
- https://github.com/markevans/dragonfly/issues/513Issue Tracking, Third Party Advisory
- https://github.com/mlr0p/CVE-2021-33564Exploit, Third Party Advisory
- https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/master/cves/2021/CVE-2021-33564.yamlExploit, Third Party Advisory
- https://zxsecurity.co.nz/research/argunment-injection-ruby-dragonfly/Exploit, Third Party Advisory
- https://github.com/markevans/dragonfly/commit/25399297bb457f7fcf8e3f91e85945b255b111b5Patch, Third Party Advisory
- https://github.com/markevans/dragonfly/compare/v1.3.0...v1.4.0Patch, Third Party Advisory
- https://github.com/markevans/dragonfly/issues/513Issue Tracking, Third Party Advisory
- https://github.com/mlr0p/CVE-2021-33564Exploit, Third Party Advisory
- https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/master/cves/2021/CVE-2021-33564.yamlExploit, Third Party Advisory
- https://zxsecurity.co.nz/research/argunment-injection-ruby-dragonfly/Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.