{"id":"GHSA-8474-xrp6-wh69","summary":"Active Support: Possible DoS vulnerability in Active Support safe_constantize","details":"### Impact\nWhen constant lookup raises `LoadError`, `ActiveSupport::Inflector#safe_constantize` (and `String#safe_constantize`) builds a regular expression from the requested constant name without escaping it, so a caller that passes untrusted input lets the attacker choose the source of a pattern that the application compiles. Crafted patterns can trigger defects in Ruby's regular expression compiler, possibly leading to a crash of the server process, and repeated requests could keep the application unavailable.\n\nAction Cable passes the `channel` value of each `subscribe` command to `safe_constantize` before any channel lookup, so in the default configuration an unauthenticated client of the Action Cable endpoint can reach this code.\n\n### Details\nThe check that decides whether `safe_constantize` returns `nil` or re-raises the `LoadError` now matches the first segment of the constant name against the error message as a literal string, and no longer compiles a regular expression. It returns the same result as before for constant names that contain no regular expression syntax.\n\n### Affected applications\nAn application is affected if it meets all of these requirements:\n- Mounts Action Cable, which a new Rails application does by default at `/cable` (`config.action_cable.mount_path`), or otherwise passes untrusted input to `safe_constantize`.\n- Accepts Action Cable connections from untrusted clients. `ApplicationCable::Connection#connect` authenticates nobody unless the application adds a check.\n\n### Workarounds\nApplications that do not use Action Cable can set `config.action_cable.mount_path = nil` to remove the endpoint. Applications that use Action Cable can call `reject_unauthorized_connection` in `ApplicationCable::Connection#connect` for unauthenticated clients, which limits exposure to authenticated users but does not remove it.\n\n### Releases\nThe fixed releases are available at the normal locations.\n\nPatches for those who cannot upgrade at once:\n- 8.1: https://github.com/rails/rails/commit/95aa9e416016524956d4904fed96eaed079580bb.patch\n- 8.0: https://github.com/rails/rails/commit/210ac22d446c8e2625b091e79256806b836eee20.patch\n\n### Versions affected\n\n- activesupport \u003c 8.0.5.2\n- activesupport \u003e= 8.1, \u003c 8.1.4.1\n\n### Credit\nThis issue was responsibly reported by Felix Tscheulin ([flixt](https://hackerone.com/flixt)) through HackerOne researcher [scheja](https://hackerone.com/scheja), and independently by Bucky Wolfe ([Igneous](https://github.com/Igneous)), who provided a proof of concept that crashes the server. It was also found by the Anthropic OSS Scanner (ANT-2026-ZUN5KU3Q).","aliases":["CVE-2026-126080"],"modified":"2026-11-10T21:45:04.323273690Z","published":"2026-11-10T21:34:11Z","database_specific":{"cwe_ids":["CWE-74"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-11-10T21:34:11Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/rails/rails/security/advisories/GHSA-8474-xrp6-wh69"},{"type":"WEB","url":"https://github.com/rails/rails/commit/210ac22d446c8e2625b091e79256806b836eee20"},{"type":"WEB","url":"https://github.com/rails/rails/commit/95aa9e416016524956d4904fed96eaed079580bb"},{"type":"PACKAGE","url":"https://github.com/rails/rails"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.0.5.2"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.1.4.1"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activesupport/GHSA-8474-xrp6-wh69.yml"}],"affected":[{"package":{"name":"activesupport","ecosystem":"RubyGems","purl":"pkg:gem/activesupport"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.1.0.beta1"},{"fixed":"8.1.4.1"}]}],"versions":["8.1.0","8.1.0.beta1","8.1.0.rc1","8.1.1","8.1.2","8.1.2.1","8.1.3","8.1.3.1","8.1.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/11/GHSA-8474-xrp6-wh69/GHSA-8474-xrp6-wh69.json"}},{"package":{"name":"activesupport","ecosystem":"RubyGems","purl":"pkg:gem/activesupport"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.5.2"}]}],"versions":["1.0.0","1.0.1","1.0.2","1.0.3","1.0.4","1.1.0","1.1.1","1.2.1","1.2.2","1.2.3","1.2.4","1.2.5","1.3.0","1.3.1","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4","2.0.0","2.0.1","2.0.2","2.0.4","2.0.5","2.1.0","2.1.1","2.1.2","2.2.2","2.2.3","2.3.10","2.3.11","2.3.12","2.3.14","2.3.15","2.3.16","2.3.17","2.3.18","2.3.2","2.3.3","2.3.4","2.3.5","2.3.6","2.3.6.pre","2.3.7","2.3.8","2.3.8.pre1","2.3.9","2.3.9.pre","3.0.0","3.0.0.beta","3.0.0.beta2","3.0.0.beta3","3.0.0.beta4","3.0.0.rc","3.0.0.rc2","3.0.1","3.0.10","3.0.10.rc1","3.0.11","3.0.12","3.0.12.rc1","3.0.13","3.0.13.rc1","3.0.14","3.0.15","3.0.16","3.0.17","3.0.18","3.0.19","3.0.2","3.0.20","3.0.3","3.0.4","3.0.4.rc1","3.0.5","3.0.5.rc1","3.0.6","3.0.6.rc1","3.0.6.rc2","3.0.7","3.0.7.rc1","3.0.7.rc2","3.0.8","3.0.8.rc1","3.0.8.rc2","3.0.8.rc4","3.0.9","3.0.9.rc1","3.0.9.rc3","3.0.9.rc4","3.0.9.rc5","3.0.pre","3.1.0","3.1.0.beta1","3.1.0.rc1","3.1.0.rc2","3.1.0.rc3","3.1.0.rc4","3.1.0.rc5","3.1.0.rc6","3.1.0.rc8","3.1.1","3.1.1.rc1","3.1.1.rc2","3.1.1.rc3","3.1.10","3.1.11","3.1.12","3.1.2","3.1.2.rc1","3.1.2.rc2","3.1.3","3.1.4","3.1.4.rc1","3.1.5","3.1.5.rc1","3.1.6","3.1.7","3.1.8","3.1.9","3.2.0","3.2.0.rc1","3.2.0.rc2","3.2.1","3.2.10","3.2.11","3.2.12","3.2.13","3.2.13.rc1","3.2.13.rc2","3.2.14","3.2.14.rc1","3.2.14.rc2","3.2.15","3.2.15.rc1","3.2.15.rc2","3.2.15.rc3","3.2.16","3.2.17","3.2.18","3.2.19","3.2.2","3.2.2.rc1","3.2.20","3.2.21","3.2.22","3.2.22.1","3.2.22.2","3.2.22.3","3.2.22.4","3.2.22.5","3.2.3","3.2.3.rc1","3.2.3.rc2","3.2.4","3.2.4.rc1","3.2.5","3.2.6","3.2.7","3.2.7.rc1","3.2.8","3.2.8.rc1","3.2.8.rc2","3.2.9","3.2.9.rc1","3.2.9.rc2","3.2.9.rc3","4.0.0","4.0.0.beta1","4.0.0.rc1","4.0.0.rc2","4.0.1","4.0.1.rc1","4.0.1.rc2","4.0.1.rc3","4.0.1.rc4","4.0.10","4.0.10.rc1","4.0.10.rc2","4.0.11","4.0.11.1","4.0.12","4.0.13","4.0.13.rc1","4.0.2","4.0.3","4.0.4","4.0.4.rc1","4.0.5","4.0.6","4.0.6.rc1","4.0.6.rc2","4.0.6.rc3","4.0.7","4.0.8","4.0.9","4.1.0","4.1.0.beta1","4.1.0.beta2","4.1.0.rc1","4.1.0.rc2","4.1.1","4.1.10","4.1.10.rc1","4.1.10.rc2","4.1.10.rc3","4.1.10.rc4","4.1.11","4.1.12","4.1.12.rc1","4.1.13","4.1.13.rc1","4.1.14","4.1.14.1","4.1.14.2","4.1.14.rc1","4.1.14.rc2","4.1.15","4.1.15.rc1","4.1.16","4.1.16.rc1","4.1.2","4.1.2.rc1","4.1.2.rc2","4.1.2.rc3","4.1.3","4.1.4","4.1.5","4.1.6","4.1.6.rc1","4.1.6.rc2","4.1.7","4.1.7.1","4.1.8","4.1.9","4.1.9.rc1","4.2.0","4.2.0.beta1","4.2.0.beta2","4.2.0.beta3","4.2.0.beta4","4.2.0.rc1","4.2.0.rc2","4.2.0.rc3","4.2.1","4.2.1.rc1","4.2.1.rc2","4.2.1.rc3","4.2.1.rc4","4.2.10","4.2.10.rc1","4.2.11","4.2.11.1","4.2.11.2","4.2.11.3","4.2.2","4.2.3","4.2.3.rc1","4.2.4","4.2.4.rc1","4.2.5","4.2.5.1","4.2.5.2","4.2.5.rc1","4.2.5.rc2","4.2.6","4.2.6.rc1","4.2.7","4.2.7.1","4.2.7.rc1","4.2.8","4.2.8.rc1","4.2.9","4.2.9.rc1","4.2.9.rc2","5.0.0","5.0.0.1","5.0.0.beta1","5.0.0.beta1.1","5.0.0.beta2","5.0.0.beta3","5.0.0.beta4","5.0.0.racecar1","5.0.0.rc1","5.0.0.rc2","5.0.1","5.0.1.rc1","5.0.1.rc2","5.0.2","5.0.2.rc1","5.0.3","5.0.4","5.0.4.rc1","5.0.5","5.0.5.rc1","5.0.5.rc2","5.0.6","5.0.6.rc1","5.0.7","5.0.7.1","5.0.7.2","5.1.0","5.1.0.beta1","5.1.0.rc1","5.1.0.rc2","5.1.1","5.1.2","5.1.2.rc1","5.1.3","5.1.3.rc1","5.1.3.rc2","5.1.3.rc3","5.1.4","5.1.4.rc1","5.1.5","5.1.5.rc1","5.1.6","5.1.6.1","5.1.6.2","5.1.7","5.1.7.rc1","5.2.0","5.2.0.beta1","5.2.0.beta2","5.2.0.rc1","5.2.0.rc2","5.2.1","5.2.1.1","5.2.1.rc1","5.2.2","5.2.2.1","5.2.2.rc1","5.2.3","5.2.3.r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