High 7.8Published Sep 17, 2026

CVE-2026-90111ip6mr: do not clone dst in ip6mr_cache_report()

Updated under an hour ago (2026-10-19 07:10 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: ip6mr: do not clone dst in ip6mr_cache_report() IPv6 input attaches a non-refcounted (NOREF) dst to skbs under RCU. When an ingress multicast packet misses MFC lookup, ip6mr_cache_unresolved() places the skb onto the unresolved queue, escaping the receive-side RCU grace period. If the underlying route is deleted and freed, and the MFC queue is later resolved with a wrong parent interface, ip6_mr_forward() invokes ip6mr_cache_report(..., MRT6MSG_WRONGMIF), which executes dst_clone(skb_dst(pkt)) on the freed dst entry, triggering a slab use-after-free. Report packets queued to mroute6_sk (a raw socket) and netlink notifications do not require an attached dst entry. Fix this by: 1. Removing dst_clone() in ip6mr_cache_report() and ensuring report skbs do not hold a dst. 2. Dropping skb_dst before queuing unresolved skbs in ip6mr_cache_unresolved(), matching the fact that multicast forwarding resolves outgoing routes anew via ip6_route_output().

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 67f415dd29063a5906c560051c00e42dcf01a4dd before f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89; 67f415dd29063a5906c560051c00e42dcf01a4dd builds before 4a674afaae4136c71943aa3e35d433676fd40e8f; from 67f415dd29063a5906c560051c00e42dcf01a4dd before 235b42b5860189eb8c27c36435ad932cae65a734	CNA record

References

https://git.kernel.org/stable/c/f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89
https://git.kernel.org/stable/c/4a674afaae4136c71943aa3e35d433676fd40e8f
https://git.kernel.org/stable/c/235b42b5860189eb8c27c36435ad932cae65a734

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.