Home/CVE/Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to v
CVE

CVE-2026-33170

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to v

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.

MEDIUM · CVSS 6.1 EPSS 0.00011
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
▤

Affected Products & Versions

3
rubyonrails rails< 7.2.3.1
rubyonrails rails>= 8.0.0 and < 8.0.4.1
rubyonrails rails>= 8.1.0 and < 8.1.2.1
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
RubyGems activesupport MODERATE fixed in 8.1.2.1
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumRuby on Rails Framework Exceptions
▣

Scoring & Timeline

6.1
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Mar 2026 · 12:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
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
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