CVE-2026-33170

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.

The following products are affected by CVE-2026-33170 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33170.

URL	Resource
https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7
https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db
https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb
https://github.com/rails/rails/releases/tag/v7.2.3.1
https://github.com/rails/rails/releases/tag/v8.0.4.1
https://github.com/rails/rails/releases/tag/v8.1.2.1
https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8v
https://nvd.nist.gov/vuln/detail/CVE-2026-33170
https://www.cve.org/CVERecord?id=CVE-2026-33170