Bug 1706044 (CVE-2018-20821)

Summary:	CVE-2018-20821 libsass: parsing component allows attackers to cause denial-of-service
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aurelien, fmuellner
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-05-15 12:11:15 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:	1706052, 1706051
Bug Blocks:	1706049

Description Dhananjay Arunesh 2019-05-03 12:37:50 UTC

The parsing component in LibSass through 3.5.5 allows attackers to cause a denial-of-service (uncontrolled recursion in Sass::Parser::parse_css_variable_value in parser.cpp).

Reference:
https://github.com/sass/libsass/issues/2658

Comment 1 Dhananjay Arunesh 2019-05-03 12:42:31 UTC

Created libsass tracking bugs for this issue:

Affects: fedora-all [bug 1706051]

Comment 2 Dhananjay Arunesh 2019-05-03 12:43:06 UTC

Created libsass tracking bugs for this issue:

Affects: epel-7 [bug 1706052]

Comment 3 Riccardo Schirone 2019-05-15 10:06:27 UTC

First vulnerable commit:
https://github.com/sass/libsass/commit/efd97dae376de50b3e6ed724337c4f274a21491d

Comment 4 Riccardo Schirone 2019-05-15 10:07:40 UTC

Upstream patch:
https://github.com/sass/libsass/commit/f2db04883e5fff4e03777dcc1eb60d4373c45be1

Comment 5 Riccardo Schirone 2019-05-15 12:11:17 UTC

Statement:

This issue did not affect the versions of libsass as shipped with Red Hat Enterprise Linux 8 as the flaw was introduced in a newer version of the library.