Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-33170— Rails Active Support has a possible XSS vulnerability in SafeBuffer#%

Quick assessment

Affected
rails activesupport
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Rails是美国Rails团队的一套基于Ruby语言的开源Web应用框架。 Rails Active Support 8.1.2.1之前版本、8.0.4.1之前版本和7.2.3.1之前版本存在跨站脚本漏洞，该漏洞源于SafeBuffer#%未传播html_unsafe标志，可能导致绕过ERB自动转义并引发跨站脚本攻击。

AI Predicted 6.1 Difficulty: Easy EPSS 0.43% · P35

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-33170

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Rails Active Support has a possible XSS vulnerability in SafeBuffer#%
Source: CVE Program / CVE List V5
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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
Rails 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Rails是美国Rails团队的一套基于Ruby语言的开源Web应用框架。 Rails Active Support 8.1.2.1之前版本、8.0.4.1之前版本和7.2.3.1之前版本存在跨站脚本漏洞，该漏洞源于SafeBuffer#%未传播html_unsafe标志，可能导致绕过ERB自动转义并引发跨站脚本攻击。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
rails activesupport >= 8.1.0.beta1, < 8.1.2.1 -

II. Public POCs for CVE-2026-33170

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-33170

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-33170 (4)

Vendor Advisories for CVE-2026-33170 (1)

Vendor Pages for CVE-2026-33170 (2)

Same Patch Batch · rails · 2026-03-23 · 9 CVEs total

CVE-2026-33195 8.0 HIGH Rails Active Storage has possible Path Traversal in DiskService
CVE-2026-33167 Rails has a possible XSS vulnerability in its Action Pack debug exceptions
CVE-2026-33168 Rails has a possible XSS vulnerability in its Action View tag helpers
CVE-2026-33176 Rails Active Support has a possible DoS vulnerability in its number helpers
CVE-2026-33173 Rails Active Storage has possible content type bypass via metadata in direct uploads
CVE-2026-33174 Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range request
CVE-2026-33169 Rails Active Support has a possible ReDoS vulnerability in number_to_delimited
CVE-2026-33202 Rails Active Storage has possible glob injection in its DiskService

IV. Related Vulnerabilities

Same product: activesupport
Same vendor: rails
Same weakness: CWE-79

V. Comments for CVE-2026-33170

No comments yet

Leave a comment