{"action":"Upgrade rack to 3.1.21 or later.","affected":[{"fixed":"3.1.21","introduced":"3.0.0.beta1"},{"fixed":"3.2.6","introduced":"3.2.0"}],"component":"rack","cve_ids":["CVE-2026-34835"],"ecosystem":"RubyGems","epss":0.002,"exploited":false,"fixed_versions":["3.1.21","3.2.6"],"ghsa_id":"GHSA-g2pf-xv49-m2h5","id":"tcs_01M5KEK74NP1FQSZBBBQAJX343","modified_at":"2026-09-10T03:50:44.295660719Z","published_at":"2026-04-02T20:36:40Z","references":["https://osv.dev/vulnerability/GHSA-g2pf-xv49-m2h5","https://github.com/rack/rack/security/advisories/GHSA-g2pf-xv49-m2h5","https://nvd.nist.gov/vuln/detail/CVE-2026-34835","https://github.com/rack/rack","https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2026-34835.yml"],"severity":{"label":"medium","score":4.8},"sources":[{"source":"osv","source_id":"GHSA-g2pf-xv49-m2h5","url":"https://osv.dev/vulnerability/GHSA-g2pf-xv49-m2h5"}],"summary":"Rack::Request accepts invalid Host characters, enabling host allowlist bypass"}