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 dst APIs.
Published: 2026-08-15
Score: n/a
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Sat, 15 Aug 2026 18:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-84

Sat, 15 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
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 dst APIs.
Title ipv6: ioam: fix type confusion of dst_entry
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-15T05:56:45.530Z

Reserved: 2026-08-09T03:40:39.928Z

Link: CVE-2026-72429

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:22:16.770

Modified: 2026-08-15T06:22:16.770

Link: CVE-2026-72429

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-15T18:00:11Z

Weaknesses