Bug 2502327 (CVE-2026-63922)

Summary:	CVE-2026-63922 kernel: ipv6: exthdrs: refresh nh after handling HAO option
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's IPv6 extension header processing. When processing the Home Address Option (HAO), the cached network header pointer may become invalid if the packet's memory is reallocated. This can lead to incorrect parsing of subsequent IPv6 Type-Length-Value (TLV) options, potentially causing unexpected network behavior or a denial of service.	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:

Description OSIDB Bzimport 2026-07-19 16:02:08 UTC

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

ipv6: exthdrs: refresh nh after handling HAO option

ip6_parse_tlv() caches skb_network_header(skb) in nh while walking
IPv6 TLVs.

ipv6_dest_hao() may call pskb_expand_head() for a cloned skb, which can
move the skb head and invalidate the cached network header pointer.
Refresh nh after ipv6_dest_hao() returns so any trailing padding or TLVs
are parsed from the current skb head.

This matches the existing pattern used in ip6_parse_tlv() after helpers
that can modify skb header storage.

Comment 1 Keith Grant 2026-07-21 21:23:02 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071948-CVE-2026-63922-5716@gregkh/T