Bug 2269836 (CVE-2021-47126)

Summary:	CVE-2021-47126 kernel: ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions
Product:	[Other] Security Response	Reporter:	Avinash Hanwate <ahanwate>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, allarkin, aquini, bhu, chwhite, cye, cyin, dbohanno, debarbos, dfreiber, drow, dvlasenk, esandeen, ezulian, hkrzesin, jarod, jburrell, jdenham, jfaracco, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, ldoskova, lgoncalv, lzampier, mleitner, mmilgram, mstowell, nmurray, ptalbert, rparrazo, rrobaina, rvrbovsk, rysulliv, scweaver, sidakwo, sukulkar, tglozar, tyberry, vkumar, wcosta, williams, wmealing, ycote, ykopkova, zhijwang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.4.125, kernel 5.10.43, kernel 5.12.10, kernel 5.13	Doc Type:	If docs needed, set a value
Doc Text:	A vulnerability was found in the Linux kernel, where an IPv6 implementation allowed a slab-out-of-bounds read in the fib6_nh_flush_exceptions function. This issue occurred when trying to free a non-allocated fib6_nh pointer, potentially leading to memory issues.	Story Points:	---
Clone Of:		Environment:
Last Closed:		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:	2269837
Bug Blocks:	2269857

Description Avinash Hanwate 2024-03-16 18:02:09 UTC

In the Linux kernel, the following vulnerability has been resolved:

ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions

The Linux kernel CVE team has assigned CVE-2021-47126 to this issue.

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024031512-CVE-2021-47126-f717@gregkh/T/#u

Comment 1 Avinash Hanwate 2024-03-16 18:02:42 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2269837]

Comment 5 Justin M. Forbes 2024-03-26 16:25:40 UTC

This was fixed for Fedora with the 5.12.10 stable kernel updates.

Comment 7 Alex 2024-06-09 15:24:03 UTC

The result of automatic check (that is developed by Alexander Larkin) for this CVE-2021-47126 is: CHECK	Maybe valid. Check manually. with impact MODERATE (that is approximation based on flags REMOTE READ KASAN OOB DISK INIT LEAK NETWORK  ; these flags parsed automatically based on patche data). Such automatic check happens only for Low/Moderates (and only when not from reporter, but parsing already existing CVE). Highs always checked manually (I check it myself and then we check it again in Remediation team). In rare cases some of the Moderates could be increased to High later.