CVE-2025-61921
HIGH7.5EPSS 0.43%Sinatra is vulnerable to ReDoS through ETag header value generation
Description
### Summary 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 and you are using Ruby < 3.2. ### Details 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 if they are using Ruby below version 3.2. ### Resources * https://github.com/sinatra/sinatra/issues/2120 (report) * https://github.com/sinatra/sinatra/pull/2121 (fix) * https://github.com/sinatra/sinatra/pull/1823 (older ReDoS vulnerability) * https://bugs.ruby-lang.org/issues/19104 (fix in Ruby >= 3.2)
Affected packages (2)
- Debian/ruby-sinatrafrom 0
- RubyGems/sinatrafrom 0, < 4.2.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS: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 |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (11)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2025-61921
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2025-61921
- PATCHhttps://github.com/sinatra/sinatra
- WEBhttps://bugs.ruby-lang.org/issues/19104
- WEBhttps://github.com/rubysec/ruby-advisory-db/blob/master/gems/sinatra/CVE-2025-61921.yml
- WEBhttps://github.com/sinatra/sinatra/commit/3fe8c38dc405586f7ad8f2ac748aa53e9c3615bd
- WEBhttps://github.com/sinatra/sinatra/commit/8ff496bd4877520599e1479d6efead39304edceb
- WEBhttps://github.com/sinatra/sinatra/issues/2120
- WEBhttps://github.com/sinatra/sinatra/pull/1823
- WEBhttps://github.com/sinatra/sinatra/pull/2121
- WEBhttps://github.com/sinatra/sinatra/security/advisories/GHSA-mr3q-g2mv-mr4q