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VulnerabilityPublished Updated

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

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89, 235b42b5860189eb8c27c36435ad932cae65a734, 42ef371466d5648f5c9e8bc219f0af0a2c2bbf8c +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 67f415dd29063a5906c560051c00e42dcf01a4dd, < f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89
Fixed in
  • f57b0fd1c62e1be274ee154ab7fb8ac4481b7f89
LinuxLinuxAffected
  • ≥ 67f415dd29063a5906c560051c00e42dcf01a4dd, < 235b42b5860189eb8c27c36435ad932cae65a734
Fixed in
  • 235b42b5860189eb8c27c36435ad932cae65a734
LinuxLinuxAffected
  • ≥ 67f415dd29063a5906c560051c00e42dcf01a4dd, < 42ef371466d5648f5c9e8bc219f0af0a2c2bbf8c
Fixed in
  • 42ef371466d5648f5c9e8bc219f0af0a2c2bbf8c
LinuxLinuxAffected
  • ≥ 67f415dd29063a5906c560051c00e42dcf01a4dd, < 7f8287f606c8c028d4224e85d95dc448c6d6d623
Fixed in
  • 7f8287f606c8c028d4224e85d95dc448c6d6d623
LinuxLinuxAffected
  • ≥ 67f415dd29063a5906c560051c00e42dcf01a4dd, < 4a674afaae4136c71943aa3e35d433676fd40e8f
Fixed in
  • 4a674afaae4136c71943aa3e35d433676fd40e8f
LinuxLinuxAffected
  • =5.3
Fixed in–

Description

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().

References

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