CVE-2026-74562High· 8.8▾ Twilight

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 n…

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score48/ 100 · Moderate

impact 48.4 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Aug 15, 2026

Updated

Oct 15, 2026

CVSS

8.8

Vendor

Linux

Product

Linux

CWE

—

Depth score

48 · Moderate

EPSS

0.17% · p6

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS history

Exploit-prediction probability, daily snapshots since Oct 15.

0.2% → 0.2%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

4 events · 62 days

Aug 15, 2026Published
Disclosed via NVD
Oct 15, 2026Record revised
Last analysed / modified upstream
Oct 15, 2026EPSS first tracked
0.2%
Oct 16, 2026EPSS peak
0.2% → 0.2%

Linux #nvd #cve.org

Affected

Linux >= 081efd18326e353c6fbfdeff903a83edde953f72 < 4b296d176580a85ccbc7135ebdf66c42087b23a2
Linux >= 081efd18326e353c6fbfdeff903a83edde953f72 < bb2b072c619c1f741a6234257050f72005dc63ef
Linux >= 081efd18326e353c6fbfdeff903a83edde953f72 < 072cd1f21819dedd2252e704d255de3b0cfc61a7
Linux 6.16

Full technical detail▾

Overview

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.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org