Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Rubyonrails | Rails | < 7.2.3.1 |
Related Weaknesses (CWE)
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
FAQ
What is CVE-2026-33170?
CVE-2026-33170 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 `@h...
How severe is CVE-2026-33170?
CVE-2026-33170 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-33170?
Check the references section above for vendor advisories and patch information. Affected products include: Rubyonrails Rails.