CVE-2026-99072
In the Linux kernel, the following vulnerability has been resolved: ipv4: stop route notification sizing when nexthop group shrinks Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware flags are changed") added an RCU-only fib_nlmsg_size() call for asynchronous hardware flag notifications. fib_nlmsg_size() checks fib_info_num_path() before each iteration, then fib_info_nhc() independently reloads nh->nh_grp. If RTM_NEWNEXTHOP replaces a group with fewer paths between those loads, fib_info_nhc() returns NULL and fib_nexthop_nlmsg_size() dereferences it. Stop sizing when the indexed path is absent. Nexthop groups are dense, so the current snapshot has no later path.
Affected versions
Linux kernel versions
5.12
and later are affected. Fixed in
6.6.160,
6.12.113,
6.18.57,
7.2.11,
7.3
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-99072?
CVE-2026-99072 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.12 onward and has been patched in 6.6.160, 6.12.113, 6.18.57 and others. CVE-2026-99072 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-99072?
Yes. CVE-2026-99072 has been patched. Fixed versions include 6.6.160, 6.12.113, 6.18.57 and others. If you are running Linux kernel 5.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-99072 actively exploited?
No. CVE-2026-99072 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.