Bug 2236834 (CVE-2020-27418)

Summary:	CVE-2020-27418 kernel: User after free via vgacon_invert_region() function
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, allarkin, bhu, chwhite, dbohanno, ddepaula, debarbos, dfreiber, dvlasenk, ezulian, hkrzesin, jarod, jburrell, jdenham, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, kernel-mgr, ldoskova, lgoncalv, lzampier, nmurray, ptalbert, qzhao, rkeshri, rogbas, rrobaina, rvrbovsk, scweaver, steve.beattie, tglozar, vkumar, walters, wcosta, williams, wmealing, ycote, ymankad
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	Kernel 5.6-rc5	Doc Type:	If docs needed, set a value
Doc Text:	A use-after-free vulnerability was found in the vgacon_invert_region in drivers/video/console/vgacon.c in the low-level VGA-based console driver in the Linux kernel. This flaw allows a local privileged attacker to crash the system due to a missing sanity check, causing a denial of service.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2236835

Description Pedro Sampaio 2023-09-01 17:22:33 UTC

A Use After Free vulnerability was found in  vgacon_invert_region in drivers/video/console/vgacon.c in Low level VGA based console driver in Linux Kernel. In this flaw, a local privileged attacker may crash the system due to a missing sanity check and cause a denial of service problem.

References:

https://patchwork.freedesktop.org/patch/356372/
http://fedora.com

Comment 8 Steve Beattie 2023-10-16 22:36:34 UTC

Hi, based on the referenced patch and description, this looks to have been fixed upstream in 513dc792d606 ("vgacon: Fix a UAF in vgacon_invert_region") <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=513dc792d606> (v5.6-rc5), which already was assigned CVE-2020-8647 and CVE-2020-8649; is this a duplicate CVE assignment?

Thanks for any clarity.