Bug 1661110 (CVE-2018-15126)

Summary:	CVE-2018-15126 libvncserver: Use-after-free in file transfer extension allows for potential code execution
Product:	[Other] Security Response	Reporter:	Sam Fowler <sfowler>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	negativo17, ppisar, rdieter
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:	2018-12-21 10:42:53 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:	1661111, 1661112
Bug Blocks:	1661105

Description Sam Fowler 2018-12-20 06:57:13 UTC

LibVNC before commit 73cb96fec028a576a5a24417b57723b55854ad7b contains a heap use-after-free vulnerability in the server code of the file transfer extension, which can result in remote code execution. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in 73cb96fec028a576a5a24417b57723b55854ad7b and later.


External Reference:

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-027-libvnc-heap-use-after-free/


Upstream Patch:

https://github.com/LibVNC/libvncserver/commit/73cb96fec028a576a5a24417b57723b55854ad7b

Comment 1 Sam Fowler 2018-12-20 06:57:26 UTC

Created libvncserver tracking bugs for this issue:

Affects: epel-7 [bug 1661112]
Affects: fedora-all [bug 1661111]

Comment 2 Sam Fowler 2018-12-20 07:37:01 UTC

Upstream Issue:

https://github.com/LibVNC/libvncserver/issues/242

Comment 3 Sam Fowler 2018-12-20 08:01:58 UTC

Reference:

https://seclists.org/oss-sec/2018/q4/212

Comment 4 Stefan Cornelius 2018-12-21 10:41:44 UTC

Statement:

This issue did not affect the versions of libvncserver as shipped with Red Hat Enterprise Linux 6 and 7, as they did not include support for tightvnc file transfer.