CVSS 4.0
5.3 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-33170
Medium (5.3) in rubyonrails rails. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in activesupport 7.2.3.1, 8.0.4.1, 8.1.2.1.
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.
Severity
CVSS 3.1
6.1 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 27% of CVEs (scores of 2026-10-31)
- CWE
- CWE-79
- Published
- Modified
- Record from
- the NVD, synced
Affected
- rubyonrails:rails
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-89vf-4333-qx8v | RubyGems | activesupport | >=8.1.0.beta1 <8.1.2.1 | 8.1.2.1 |
| GHSA-89vf-4333-qx8v | RubyGems | activesupport | >=8.0.0.beta1 <8.0.4.1 | 8.0.4.1 |
| GHSA-89vf-4333-qx8v | RubyGems | activesupport | <7.2.3.1 | 7.2.3.1 |
References
- 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