{"id":"UBUNTU-CVE-2025-61921","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.","modified":"2026-07-31T01:55:18.498130691Z","published":"2025-10-10T20:15:00Z","related":["USN-8624-1"],"upstream":["CVE-2025-61921"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-61921"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-61921"},{"type":"REPORT","url":"https://github.com/sinatra/sinatra/security/advisories/GHSA-mr3q-g2mv-mr4q"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8624-1"}],"affected":[{"package":{"name":"ruby-sinatra","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ruby-sinatra?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.7-3ubuntu0.1~esm3"}]}],"versions":["1.4.6-2","1.4.7-3","1.4.7-3ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-sinatra","binary_version":"1.4.7-3ubuntu0.1~esm3"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-61921.json"}},{"package":{"name":"ruby-sinatra","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/ruby-sinatra?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.8-1ubuntu0.1~esm3"}]}],"versions":["1.4.7-5","1.4.8-1","1.4.8-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-sinatra","binary_version":"1.4.8-1ubuntu0.1~esm3"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-61921.json"}},{"package":{"name":"ruby-sinatra","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/ruby-sinatra?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.8.1-2+deb11u1ubuntu0.1~esm1"}]}],"versions":["2.0.8.1-2","2.0.8.1-2+deb11u1build0.22.04.1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.0.8.1-2+deb11u1ubuntu0.1~esm1","binary_name":"ruby-rack-protection"},{"binary_name":"ruby-sinatra","binary_version":"2.0.8.1-2+deb11u1ubuntu0.1~esm1"},{"binary_name":"ruby-sinatra-contrib","binary_version":"2.0.8.1-2+deb11u1ubuntu0.1~esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-61921.json"}},{"package":{"name":"ruby-sinatra","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/ruby-sinatra?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.1-1"}]}],"versions":["4.1.1-5"],"ecosystem_specific":{"binaries":[{"binary_name":"ruby-rack-protection","binary_version":"4.2.1-1"},{"binary_name":"ruby-sinatra","binary_version":"4.2.1-1"},{"binary_name":"ruby-sinatra-contrib","binary_version":"4.2.1-1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-61921.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}