Bug 2424860 (CVE-2025-68353)

Summary:	CVE-2025-68353 kernel: Kernel: Denial of Service via NULL pointer dereference in VXLAN module
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's Virtual Extensible LAN (VXLAN) module. This vulnerability allows a local user to cause a system crash, leading to a Denial of Service (DoS). The issue occurs due to a NULL pointer dereference, which is an attempt to access a memory location that does not exist, when network interface pointers (sock4 or sock6) are not guaranteed to be non-NULL, such as when the interface is brought down.	Story Points:	---
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-12-24 11:01:39 UTC

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

net: vxlan: prevent NULL deref in vxlan_xmit_one

Neither sock4 nor sock6 pointers are guaranteed to be non-NULL in
vxlan_xmit_one, e.g. if the iface is brought down. This can lead to the
following NULL dereference:

  BUG: kernel NULL pointer dereference, address: 0000000000000010
  Oops: Oops: 0000 [#1] SMP NOPTI
  RIP: 0010:vxlan_xmit_one+0xbb3/0x1580
  Call Trace:
   vxlan_xmit+0x429/0x610
   dev_hard_start_xmit+0x55/0xa0
   __dev_queue_xmit+0x6d0/0x7f0
   ip_finish_output2+0x24b/0x590
   ip_output+0x63/0x110

Mentioned commits changed the code path in vxlan_xmit_one and as a side
effect the sock4/6 pointer validity checks in vxlan(6)_get_route were
lost. Fix this by adding back checks.

Since both commits being fixed were released in the same version (v6.7)
and are strongly related, bundle the fixes in a single commit.

Comment 1 Vipul Nair 2025-12-24 13:17:09 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025122455-CVE-2025-68353-8704@gregkh/T