CVE-2026-72429

Technical Description

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

ipv6: ioam: fix type confusion of dst_entry

IOAM uses a dummy dst_entry(null_dst) to mark that the destination should

not be changed after the transformation. This dst is stored in the IOAM lwt

state and may be passed to dst_cache_set_ip6().

However, the IPv6 dst cache path eventually calls rt6_get_cookie(), which

treats the dst_entry as part of a struct rt6_info. Since the null_dst was

embedded directly as a struct dst_entry in struct ioam6_lwt, this resulted

in an invalid cast and rt6_get_cookie() reading fields from the wrong

object.

In practice, the wrong cookie is not used while dst->obsolete is zero, but

rt6_get_cookie() may also access per-cpu value when rt->sernum is

zero. In this case, rt->sernum aliases ioam6_lwt::cache::reset_ts, which

can become zero, making this a potential invalid pointer access.

Fix this by embedding a full struct rt6_info for the dummy IPv6 route and

passing its dst member to the d

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References