Bug 2466996 (CVE-2026-43101)

Summary:	CVE-2026-43101 kernel: ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 In-situ Operations, Administration, and Maintenance (IOAM) subsystem. The `__ioam6_fill_trace_data()` function did not properly check for NULL values, which could lead to NULL dereferences. A local or remote attacker could potentially trigger this flaw, resulting in a system crash and 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 2026-05-06 10:02:24 UTC

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

ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data()

We need to check __in6_dev_get() for possible NULL value, as
suggested by Yiming Qian.

Also add skb_dst_dev_rcu() instead of skb_dst_dev(),
and two missing READ_ONCE().

Note that @dev can't be NULL.

Comment 1 Alexander B 2026-05-06 14:42:30 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050621-CVE-2026-43101-7e6e@gregkh/T