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Linux Kernel xfrm Bundle Holds a Stale dst->dev After RTM_DELLINK, Producing a Use-After-Free

Last refreshed2026-10-10

Status: UPDATED  |  Advisory ID: CVE-2026-98364

Key Details

CVECVE-2026-98364
CVSS Score / Version7.8 (High) / CVSS v3.1
Updated2026-10-07
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Proseattack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected productsLinux Kernel

Affected Products, Subsystems & Sectors

VendorProductAffected VersionsPatch Status
LinuxLinux Kernel
SubsystemsOT Supporting Infrastructure
SectorsAll Sectors

What to Know

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

xfrm: hold net_device reference under RCU in bundle creation

xfrm_bundle_create() and xfrm_create_dummy_bundle() read dst->dev into

a local pointer without taking a device reference, then pass it to

xfrm_fill_dst(). A concurrent RTM_DELLINK replaces dst->dev via

dst_dev_put() and frees the old net_device, causing a use-after-free

when xfrm6_fill_dst() later dereferences the stale dev pointer.

BUG: KASAN: slab-use-after-free in xfrm6_fill_dst+0x82c/0x860

(net/ipv6/xfrm6_policy.c:86 netdev_hold())

Read of size 8 at addr ffff8880142fe588 by task exploit/153

Call Trace:

xfrm6_fill_dst+0x82c/0x860

xfrm_resolve_and_create_bundle+0x21d4/0x2bd0

xfrm_lookup_with_ifid+0x485/0x1640

ip6_dst_lookup_flow+0x19b/0x1e0

udpv6_sendmsg+0x1443/0x2dd0

Fix this by reading dst->dev via dst_dev_rcu() and keeping the RCU

read-side critical section active until xfrm_fill_dst() has taken the

required device references. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-98364
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-98364