In the Linux kernel, the following vulnerability has been resolved:
ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops
fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.
As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic.
Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade bpftool6.18Upgrade bpftool6.18-debuginfoUpgrade python3-perf6.18Upgrade perf6.18Upgrade kernel6.18-tools-develUpgrade perf6.18-debuginfoUpgrade kernel6.18-modules-extraUpgrade kernel6.18-toolsUpgrade microvm-kernel6.18Upgrade python3-perf6.18-debuginfoUpgrade kernel6.18-tools-debuginfoUpgrade kernel6.18-develUpgrade kernel6.18-debuginfo-common-aarch64Upgrade kernel6.18-modules-extra-commonUpgrade kernel6.18-headersUpgrade kernel-livepatch-6.18.48-107.148Upgrade kernel6.18-debuginfo-common-x86_64Upgrade kernel6.18-debuginfoUpgrade kernel6.18 | Sep 30, 2026 | Aug 22, 2026 |
| Debian | — | Upgrade linuxUpgrade linux-6.12 | Aug 26, 2026 | Aug 26, 2026 |
| Redhat_linux | — | No solution exists | Aug 26, 2026 | Aug 22, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Sep 15, 2026 | Aug 22, 2026 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub