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VulnerabilityPublished Updated

CVE-2026-74562: Linux kernel · nexthop: take nh->lock for f6i_list walks in replace check and notify

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 8.8 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
8.8High
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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Aug 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

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-5.5 – 7.0.0-31.31
21 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1002.2 – 7.0.0-1012.12
13 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1003.3 – 7.0.0-1014.14
14 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1003.3 – 7.0.0-1013.13
8 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threatsAffected
  • 6.17.0-1002.2 – 7.0.0-1011.11
11 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1002.3 – 7.0.0-1006.7
4 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: nexthop: take nh->lock for f6i_list walks in replace check and notify fib6_check_nh_list() and __nexthop_replace_notify() walk nh->f6i_list during an RTNL-serialized nexthop replace without holding nh->lock. IPv6 RTM_NEWROUTE/RTM_DELROUTE run without RTNL and mutate that list under nh->lock (fib6_add_rt2node_nh(), fib6_purge_rt()), so both walks race a concurrent route delete that unlinks and frees a fib6_info: BUG: KASAN: slab-use-after-free in rt6_fill_node.isra.0 (net/ipv6/route.c:5799) Read of size 4 at addr ffff888014607e64 by task exploit/143 rt6_fill_node.isra.0 (net/ipv6/route.c:5799) fib6_rt_update (net/ipv6/route.c:6412) __nexthop_replace_notify (net/ipv4/nexthop.c:2542) rtm_new_nexthop (net/ipv4/nexthop.c:2554) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) BUG: KASAN: slab-use-after-free in fib6_check_nh_list (net/ipv4/nexthop.c:1605) Read of size 8 at addr ffff888014a7d068 by task exploit/142 fib6_check_nh_list (net/ipv4/nexthop.c:1605) rtm_new_nexthop (net/ipv4/nexthop.c:2575) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) Both walks only read the entries and take no tb6_lock, so protect them with nh->lock; fib6_rt_update() uses gfp_any(), which returns GFP_ATOMIC under the lock.

References

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