{"id":"CVE-2026-26962","aliases":["GHSA-rx22-g9mx-qrhv"],"url":"https://o3.security/vulnerability/CVE-2026-26962","summary":"Rack: Header injection in multipart requests","details":"Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.","published":"2026-04-02T17:10:17.091Z","modified":"2026-07-27T03:56:44.013061515Z","cvss":{"score":4.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"rack","fixedVersion":"3.2.6"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26962.json"},{"type":"ADVISORY","url":"https://github.com/rack/rack/security/advisories/GHSA-rx22-g9mx-qrhv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26962"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-27T03:56:44.013061515Z"}}