CVE intelligence and bounded remediation

CVE-2026-46099 — Linux Linux Kernel security vulnerability

High CVSS 8.1

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels seg6_input_core() and rpl_input() call ip6_route_input() which sets a NOREF dst on the skb, then pass it to dst_cache_set_ip6() invoking dst_hold() unconditionally. On PREEMPT_RT, ksoftirqd is preemptible and a higher-priority task can release the underlying pcpu_rt between the lookup and the caching through a concurrent FIB lookup on a shared nexthop. Simplified race sequence: ksoftirqd/X higher-prio task (same CPU X) ----------- -------------------------------- seg6_input_core(,skb)/rpl_input(skb) dst_cache_get() -> miss ip6_route_input(skb) -> ip6_pol_route(,skb,flags) [RT6_LOOKUP_F_DST_NOREF in flags] -> FIB lookup resolves fib6_nh [nhid=N route] -> rt6_make_pcpu_route() [creates pcpu_rt, refcount=1] pcpu_rt->sernum = fib6_sernum [fib6_sernum=W] -> cmpxchg(fib6_nh.rt6i_pcpu, NULL, pcpu_rt) [slot was empty, store succeeds] -> skb_dst_set_noref(skb, dst) [dst is pcpu_rt, refcount still 1] rt_genid_bump_ipv6() -> bumps fib6_sernum [fib6_sernum from W to Z] ip6_route_output() -> ip6_pol_route() -> FIB lookup resolves fib6_nh [nhid=N] -> rt6_get_pcpu_route() pc…

Severity
High
CVSS
8.1 (3.1)
Published
2026-05-27
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-911

Affected products

  • linux / linux_kernel
  • linux / linux_kernel / 7.1

Showing 2 representative product identities from 7 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

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Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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