{"id":"CVE-2020-8264","aliases":["GHSA-35mm-cc6r-8fjp"],"url":"https://o3.security/vulnerability/CVE-2020-8264","summary":"Cross-site scripting in actionpack","details":"In actionpack gem >= 6.0.0, a possible XSS vulnerability exists when an application is running in development mode allowing an attacker to send or embed (in another page) a specially crafted URL which can allow the attacker to execute JavaScript in the context of the local application. This vulnerability is in the Actionable Exceptions middleware.\n\nWorkarounds\n-----------\nUntil such time as the patch can be applied, application developers should disable the Actionable Exceptions middleware in their development environment via a line such as this one in their config/environment/development.rb: `config.middleware.delete ActionDispatch::ActionableExceptions`","published":"2021-01-06T21:15:14.363Z","modified":"2026-09-09T08:15:07.676622Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"RubyGems","name":"actionpack","fixedVersion":"6.0.3.4"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://groups.google.com/g/rubyonrails-security/c/yQzUVfv42jk/m/oJWw-xhNAQAJ"},{"type":"FIX","url":"https://hackerone.com/reports/904059"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-8264"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2020-8264.yml"},{"type":"WEB","url":"https://groups.google.com/g/rubyonrails-security/c/yQzUVfv42jk"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-09T08:15:07.676622Z"}}