CVE-2025-61921
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.
Does this matter?
Lower severity and a low EPSS score (0.50%). Track it; it rarely justifies an emergency change on its own.
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 4.0
- 2.7 LOWCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.50% probability · 41th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-1333
- Affected
- sinatrarb/sinatra
- Source
- security-advisories@github.com
References
- https://bugs.ruby-lang.org/issues/19104Issue Tracking
- https://github.com/sinatra/sinatra/issues/2120Issue Tracking
- https://github.com/sinatra/sinatra/pull/1823Exploit, Patch
- https://github.com/sinatra/sinatra/pull/2121Patch
- https://github.com/sinatra/sinatra/security/advisories/GHSA-mr3q-g2mv-mr4qVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.