Bug 1568842 (CVE-2018-3741)

Summary: CVE-2018-3741 rubygem-rails-html-sanitizer: non-whitelisted attributes are present in sanitized output when input with specially-crafted HTML fragments leading to XSS vulnerability
Product: [Other] Security Response Reporter: Adam Mariš <amaris>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: cpelland, dajohnso, dmetzger, gblomqui, gmccullo, gtanzill, hhorak, hhudgeon, jaruga, jhardy, jorton, jprause, kdixon, pvalena, roliveri, ruby-maint, simaishi, strzibny, vondruch
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: rubygem-rails-html-sanitizer 1.0.4 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-10-21 20:01:06 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1559658, 1568845, 1569130, 1569131, 1576590, 1576591    
Bug Blocks: 1568847    

Description Adam Mariš 2018-04-18 10:17:48 UTC 
There is a possible XSS vulnerability in all rails-html-sanitizer gem versions below 1.0.4 for Ruby. The gem allows non-whitelisted attributes to be present in sanitized output when input with specially-crafted HTML fragments, and these attributes can lead to an XSS attack on target applications. This issue is similar to CVE-2018-8048 in Loofah. All users running an affected release should either upgrade or use one of the workarounds immediately.

Upstream fix:

https://github.com/rails/rails-html-sanitizer/commit/f3ba1a839a35f2ba7f941c15e239a1cb379d56ae
Comment 1 Adam Mariš 2018-04-18 10:18:19 UTC 
Created rubygem-rails-html-sanitizer tracking bugs for this issue:

Affects: fedora-all [bug 1568845]
Comment 7 Richard Maciel Costa 2018-12-18 19:52:00 UTC 
Statement:

This issue affects the versions of rubygem-rails-html-sanitizer as shipped with Red Hat CloudForms 4. Red Hat Product Security has rated this issue as having a security  impact of Moderate. This vulnerability won't be fixed on CloudForms 4, because it uses libxml 2.9.1 and since the vulnerability requires a libxml >= 2.9.2 in order to be exploitable. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/