{"id":"CVE-2026-33170","aliases":["GHSA-89vf-4333-qx8v"],"url":"https://o3.security/vulnerability/CVE-2026-33170","summary":"Rails Active Support has a possible XSS vulnerability in SafeBuffer#%","details":"Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `SafeBuffer#%` does not propagate the `@html_unsafe` flag to the newly created buffer. If a `SafeBuffer` is mutated in place (e.g. via `gsub!`) and then formatted with `%` using untrusted arguments, the result incorrectly reports `html_safe? == true`, bypassing ERB auto-escaping and possibly leading to XSS. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.","published":"2026-03-23T23:09:48.923Z","modified":"2026-08-07T11:49:52.486789596Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"activesupport","fixedVersion":"8.1.2.1"},{"ecosystem":"RubyGems","name":"activesupport","fixedVersion":"8.0.4.1"},{"ecosystem":"RubyGems","name":"activesupport","fixedVersion":"7.2.3.1"}],"fix":{"url":"https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7","label":"rails/rails@50d732a"},"references":[{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v7.2.3.1"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.0.4.1"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.1.2.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33170.json"},{"type":"ADVISORY","url":"https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33170"},{"type":"FIX","url":"https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7"},{"type":"FIX","url":"https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db"},{"type":"FIX","url":"https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:49:52.486789596Z"}}