CVE Tools
Sign in

CVE-2026-33170

Rails Active Support has a possible XSS vulnerability in SafeBuffer#%

Published: Mar 23, 2026Updated: Mar 24, 2026 Sources: CVE List NVD BDUCWE-79
6.1MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 74.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-79

Affected Products

rubyonrails
oss-project·USaka rails, rubyonrails.org, ruby on rails
rails
OSS Libraries
rails
oss-projectaka rails-html-sanitizer, activestorage
activesupportLibrary
OSS Libraries / web-framework
ООО «Ред Софт»
commercial·RUaka red soft
РЕД ОСOn-premOS
Operating Systems / linux-distro
Red Hat Inc.
commercial·USaka red hat
Red Hat SatelliteOn-prem
Operating Systems / linux-distro
Rails Core Team
oss-projectaka rubyonrails, rack? no, actionview, rails
Ruby on RailsLibrary
OSS Libraries / web-framework

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

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
and 14 more references View all →

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-33170 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows