Vulnerability Description
Sinatra is a domain-specific language for creating web applications in Ruby. In versions prior to 4.2.0, there is a denial of service vulnerability in the `If-Match` and `If-None-Match` header parsing component of Sinatra, if the `etag` method is used when constructing the response. Carefully crafted input can cause `If-Match` and `If-None-Match` header parsing in Sinatra to take an unexpected amount of time, possibly resulting in a denial of service attack vector. This header is typically involved in generating the `ETag` header value. Any applications that use the `etag` method when generating a response are impacted. Version 4.2.0 fixes the issue.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Sinatrarb | Sinatra | < 4.2.0 |
Related Weaknesses (CWE)
References
- https://bugs.ruby-lang.org/issues/19104Issue Tracking
- https://github.com/sinatra/sinatra/issues/2120Issue Tracking
- https://github.com/sinatra/sinatra/pull/1823ExploitPatch
- https://github.com/sinatra/sinatra/pull/2121Patch
- https://github.com/sinatra/sinatra/security/advisories/GHSA-mr3q-g2mv-mr4qVendor Advisory
FAQ
What is CVE-2025-61921?
CVE-2025-61921 is a vulnerability with a CVSS score of 7.5 (HIGH). Sinatra is a domain-specific language for creating web applications in Ruby. In versions prior to 4.2.0, there is a denial of service vulnerability in the `If-Match` and `If-None-Match` header parsing...
How severe is CVE-2025-61921?
CVE-2025-61921 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-61921?
Check the references section above for vendor advisories and patch information. Affected products include: Sinatrarb Sinatra.