CVE-2026-33170

MEDIUM EPSS 24.5%
Published Mar 24, 20263mo ago · Modified Jun 17, 20262w ago
5.3 CVSS 4.0
Medium
Find Similar
Published Mar 24, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
5.3
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction P
Scope X

Threat Intelligence

EPSS Exploit Probability
24.5% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-79 Cross-site Scripting Injection

Affected Products 3

VendorProductVersionRange
rubyonrailsrails* <7.2.3.1
rubyonrailsrails*≥8.0.0  –  <8.0.4.1
rubyonrailsrails*≥8.1.0  –  <8.1.2.1

References 7

  • github.com https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7
    Patch
  • github.com https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db
    Patch
  • github.com https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb
    Patch
  • github.com https://github.com/rails/rails/releases/tag/v7.2.3.1
    Release Notes
  • github.com https://github.com/rails/rails/releases/tag/v8.0.4.1
    Release Notes
  • github.com https://github.com/rails/rails/releases/tag/v8.1.2.1
    Release Notes
  • github.com https://github.com/rails/rails/security/advisories/GHSA-89vf-4333-qx8v
    Vendor Advisory

Remediation

  • github.com https://github.com/rails/rails/commit/50d732af3b7c8aaf63cbcca0becbc00279b215b7
    Patch
  • github.com https://github.com/rails/rails/commit/6e8a81108001d58043de9e54a06fca58962fc2db
    Patch
  • github.com https://github.com/rails/rails/commit/c1ad0e8e1972032f3395853a5e99cea035035beb
    Patch