Description
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.
Metrics
CVSS 3.1 6.1/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| rails | activesupport | >= 8.1.0.beta1, < 8.1.2.1; >= 8.0.0.beta1, < 8.0.4.1; < 7.2.3.1 |
References
- https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7Patch
- https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2dbPatch
- https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035bebPatch
- https://github.com/rails/rails/releases/tag/v7.2.3.1Release Notes
- https://github.com/rails/rails/releases/tag/v8.0.4.1Release Notes
- https://github.com/rails/rails/releases/tag/v8.1.2.1Release Notes
- https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8vVendor Advisory
Timeline
- Published
- Mar 24, 2026
- Last modified
- Jun 17, 2026
- NVD status
- Analyzed