Bug 1671377 (CVE-2018-19827) - CVE-2018-19827 libsass: Use-after-free in SharedPtr class resulting in a denial of service
Summary: CVE-2018-19827 libsass: Use-after-free in SharedPtr class resulting in a deni...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2018-19827
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1671395 1671396 1677702
Blocks: 1671393
TreeView+ depends on / blocked
 
Reported: 2019-01-31 14:01 UTC by Andrej Nemec
Modified: 2019-09-29 15:07 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2019-06-10 10:47:00 UTC
Embargoed:

Attachments (Terms of Use)

Description Andrej Nemec 2019-01-31 14:01:50 UTC 
In LibSass 3.5.5, a use-after-free vulnerability exists in the SharedPtr class in SharedPtr.cpp (or SharedPtr.hpp) that may cause a denial of service (application crash) or possibly have unspecified other impact.

Upstream issue:

https://github.com/sass/libsass/issues/2782
Comment 1 Andrej Nemec 2019-01-31 14:16:30 UTC 
Created libsass tracking bugs for this issue:

Affects: epel-7 [bug 1671396]
Affects: fedora-all [bug 1671395]
Comment 2 Riccardo Schirone 2019-02-15 14:49:10 UTC 
Upstraem patch:
https://github.com/sass/libsass/commit/67a3f4ff9b790ed016197e6da4ef4e1d4c9da09f
Comment 3 Riccardo Schirone 2019-02-15 15:24:08 UTC 
The use-after-free reported by ASAN is actually caused by a type confusion. In particular, function Expand::operator() in expand.cpp calls Expand::selector() which returns a Selector_List_Obj object. However, the result is assigned to a variable of type Selector_List_Ptr. This can lead to accessing invalid memory or possibly executing arbitrary code.
Note You need to log in before you can comment on or make changes to this bug.