CVE-2026-33170
Rails Active Support has a possible XSS vulnerability in SafeBuffer#%
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
2th
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.
| CWE | CWE-79 |
| Vendor | rails |
| Product | activesupport |
| Published | Mar 23, 2026 |
| Last Updated | Mar 25, 2026 |
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Affected Versions
rails / activesupport
>= 8.1.0.beta1, < 8.1.2.1 >= 8.0.0.beta1, < 8.0.4.1 < 7.2.3.1
References
github.com: https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8v github.com: https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7 github.com: https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db github.com: https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb github.com: https://github.com/rails/rails/releases/tag/v7.2.3.1 github.com: https://github.com/rails/rails/releases/tag/v8.0.4.1 github.com: https://github.com/rails/rails/releases/tag/v8.1.2.1