{"id":"CVE-2025-61921","aliases":["GHSA-mr3q-g2mv-mr4q"],"url":"https://o3.security/vulnerability/CVE-2025-61921","summary":"Sinatra has ReDoS vulnerability in ETag header value generation","details":"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.","published":"2025-10-10T19:28:10.688Z","modified":"2026-07-15T01:49:02.958631905Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"sinatra","fixedVersion":"4.2.0"}],"fix":{"url":"https://github.com/sinatra/sinatra/pull/1823","label":"sinatra/sinatra#1823"},"references":[{"type":"WEB","url":"https://bugs.ruby-lang.org/issues/19104"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/61xxx/CVE-2025-61921.json"},{"type":"ADVISORY","url":"https://github.com/sinatra/sinatra/security/advisories/GHSA-mr3q-g2mv-mr4q"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-61921"},{"type":"REPORT","url":"https://github.com/sinatra/sinatra/issues/2120"},{"type":"FIX","url":"https://github.com/sinatra/sinatra/pull/1823"},{"type":"FIX","url":"https://github.com/sinatra/sinatra/pull/2121"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:02.958631905Z"}}