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Fencer Intel
high 8.1

CVE-2026-46099 json

net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels

published 5mo ago modified 21d ago also EUVD-2026-32482

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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() pcpu_rt->sernum != fib6_sernum [W <> Z, stale] -> prev = xchg(rt6i_pcpu, NULL) -> dst_release(prev) [prev is pcpu_rt, refcount 1->0, dead]

dst = skb_dst(skb) [dst is the dead pcpu_rt] dst_cache_set_ip6(dst) -> dst_hold() on dead dst -> WARN / use-after-free

For the race to occur, ksoftirqd must be preemptible (PREEMPT_RT without PREEMPT_RT_NEEDS_BH_LOCK) and a concurrent task must be able to release the pcpu_rt. Shared nexthop objects provide such a path, as two routes pointing to the same nhid share the same fib6_nh and its rt6i_pcpu entry.

Fix seg6_input_core() and rpl_input() by calling skb_dst_force() after ip6_route_input() to force the NOREF dst into a refcounted one before caching. The output path is not affected as ip6_route_output() already returns a refcounted dst.

Patch / fix

  • Linux Linux 7.1
  • Red Hat Red Hat Enterprise Linux 10 0:6.12.0-211.39.1.el10_2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:6.12.0-55.103.1.el10_0
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:5.14.0-284.188.1.el9_2, 0:5.14.0-284.188.1.rt14.473.el9_2
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:5.14.0-570.138.1.el9_6
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.86-1
  • linux Debian 14 7.0.4-1

debian advisories DEBIAN-CVE-2026-46099

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72

ubuntu advisories UBUNTU-CVE-2026-46099

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.39.1.el10_2
  • rv RHEL 10.2 6.12.0-211.39.1.el10_2
  • perf RHEL 10.2 6.12.0-211.39.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.39.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.39.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.39.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.39.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.39.1.el10_2

red hat advisories RHSA-2026:65712RHSA-2026:64767RHSA-2026:62568RHSA-2026:59662RHSA-2026:59663RHSA-2026:45114

  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-50.2
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-50.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-50.1
  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-50.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-50.2
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.73.2
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.73.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.73.2

suse advisories SUSE-SU-2026:22810-1SUSE-SU-2026:22809-1SUSE-SU-2026:22904-1SUSE-SU-2026:22903-1SUSE-SU-2026:3166-1SUSE-SU-2026:22742-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.36.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.36.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.36.1

opensuse advisories openSUSE-SU-2026:21388-1openSUSE-SU-2026:10954-1

  • kernel AlmaLinux 10 6.12.0-211.39.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.39.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.39.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.39.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.39.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.39.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.39.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.39.1.el10_2

almalinux advisories ALSA-2026:45114ALSA-2026:43307

  • kernel Rocky Linux 10 6.12.0-211.39.1.el10_2

rocky linux advisories RLSA-2026:45114

  • kernel Azure Linux 3.0 6.6.141.1-1

azure linux advisories AZL-88526

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-46099 updated cvss 7.3

kernel: net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.138.1.el9_6
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.39.1.el10_2, perf 6.12.0-211.39.1.el10_2, rtla 6.12.0-211.39.1.el10_2, python3-perf 6.12.0-211.39.1.el10_2, kernel-devel-matched 6.12.0-211.39.1.el10_2, kernel-64k-devel-matched 6.12.0-211.39.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.188.1.el9_2, rtla 5.14.0-284.188.1.el9_2, kernel-devel-matched 5.14.0-284.188.1.el9_2, kernel-64k-devel-matched 5.14.0-284.188.1.el9_2, kernel-debug-devel-matched 5.14.0-284.188.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.188.1.el9_2, +5 more
    fixed: vendor fix RHSA-2026:59662
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.149.1.el9_4, perf 5.14.0-427.149.1.el9_4, rtla 5.14.0-427.149.1.el9_4, kernel-devel-matched 5.14.0-427.149.1.el9_4, kernel-64k-devel-matched 5.14.0-427.149.1.el9_4, kernel-debug-devel-matched 5.14.0-427.149.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:65712
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.103.1.el10_0, perf 6.12.0-55.103.1.el10_0, rtla 6.12.0-55.103.1.el10_0, python3-perf 6.12.0-55.103.1.el10_0, kernel-devel-matched 6.12.0-55.103.1.el10_0, kernel-64k-devel-matched 6.12.0-55.103.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:64767
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.138.1.el9_6, perf 5.14.0-570.138.1.el9_6, rtla 5.14.0-570.138.1.el9_6, python3-perf 5.14.0-570.138.1.el9_6, kernel-devel-matched 5.14.0-570.138.1.el9_6, kernel-64k-devel-matched 5.14.0-570.138.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.39.1.el10_2, kernel-64k 6.12.0-211.39.1.el10_2, kernel-core 6.12.0-211.39.1.el10_2, kernel-tools 6.12.0-211.39.1.el10_2, kernel-modules 6.12.0-211.39.1.el10_2, kernel-64k-core 6.12.0-211.39.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:45114
show 17 more
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.188.1.el9_2, kernel 5.14.0-284.188.1.el9_2, kernel-64k 5.14.0-284.188.1.el9_2, kernel-core 5.14.0-284.188.1.el9_2, kernel-tools 5.14.0-284.188.1.el9_2, python3-perf 5.14.0-284.188.1.el9_2, +28 more
    fixed: vendor fix RHSA-2026:59662
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.149.1.el9_4, kernel 5.14.0-427.149.1.el9_4, kernel-64k 5.14.0-427.149.1.el9_4, kernel-core 5.14.0-427.149.1.el9_4, kernel-tools 5.14.0-427.149.1.el9_4, python3-perf 5.14.0-427.149.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:65712
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.103.1.el10_0, kernel-64k 6.12.0-55.103.1.el10_0, kernel-core 6.12.0-55.103.1.el10_0, kernel-tools 6.12.0-55.103.1.el10_0, kernel-modules 6.12.0-55.103.1.el10_0, kernel-64k-core 6.12.0-55.103.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:64767
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.138.1.el9_6, kernel-64k 5.14.0-570.138.1.el9_6, kernel-core 5.14.0-570.138.1.el9_6, kernel-tools 5.14.0-570.138.1.el9_6, kernel-modules 5.14.0-570.138.1.el9_6, kernel-64k-core 5.14.0-570.138.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.39.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.39.1.el10_2
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.103.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.103.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.103.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.103.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.103.1.el10_0
    fixed: vendor fix RHSA-2026:64767
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.39.1.el10_2, kernel-rt-64k 6.12.0-211.39.1.el10_2, kernel-rt-core 6.12.0-211.39.1.el10_2, kernel-rt-modules 6.12.0-211.39.1.el10_2, kernel-rt-64k-core 6.12.0-211.39.1.el10_2, kernel-rt-debug-core 6.12.0-211.39.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-core 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-modules 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-debug-core 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-modules-core 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-debug-modules 5.14.0-284.188.1.rt14.473.el9_2, +4 more
    fixed: vendor fix RHSA-2026:59663
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.149.1.el9_4, kernel-rt-core 5.14.0-427.149.1.el9_4, kernel-rt-modules 5.14.0-427.149.1.el9_4, kernel-rt-debug-core 5.14.0-427.149.1.el9_4, kernel-rt-modules-core 5.14.0-427.149.1.el9_4, kernel-rt-debug-modules 5.14.0-427.149.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:65712
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.103.1.el10_0, kernel-rt-64k 6.12.0-55.103.1.el10_0, kernel-rt-core 6.12.0-55.103.1.el10_0, kernel-rt-modules 6.12.0-55.103.1.el10_0, kernel-rt-64k-core 6.12.0-55.103.1.el10_0, kernel-rt-debug-core 6.12.0-55.103.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:64767
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.138.1.el9_6, kernel-rt-64k 5.14.0-570.138.1.el9_6, kernel-rt-core 5.14.0-570.138.1.el9_6, kernel-rt-modules 5.14.0-570.138.1.el9_6, kernel-rt-64k-core 5.14.0-570.138.1.el9_6, kernel-rt-debug-core 5.14.0-570.138.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.39.1.el10_2, kernel-rt-core 6.12.0-211.39.1.el10_2, kernel-rt-modules 6.12.0-211.39.1.el10_2, kernel-rt-debug-core 6.12.0-211.39.1.el10_2, kernel-rt-modules-core 6.12.0-211.39.1.el10_2, kernel-rt-debug-modules 6.12.0-211.39.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:45114
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-kvm 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-core 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-modules 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-debug-kvm 5.14.0-284.188.1.rt14.473.el9_2, kernel-rt-debug-core 5.14.0-284.188.1.rt14.473.el9_2, +6 more
    fixed: vendor fix RHSA-2026:59663
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.149.1.el9_4, kernel-rt-kvm 5.14.0-427.149.1.el9_4, kernel-rt-core 5.14.0-427.149.1.el9_4, kernel-rt-modules 5.14.0-427.149.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.149.1.el9_4, kernel-rt-debug-core 5.14.0-427.149.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:65712
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.103.1.el10_0, kernel-rt-kvm 6.12.0-55.103.1.el10_0, kernel-rt-core 6.12.0-55.103.1.el10_0, kernel-rt-modules 6.12.0-55.103.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.103.1.el10_0, kernel-rt-debug-core 6.12.0-55.103.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:64767
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.138.1.el9_6, kernel-rt-kvm 5.14.0-570.138.1.el9_6, kernel-rt-core 5.14.0-570.138.1.el9_6, kernel-rt-modules 5.14.0-570.138.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.138.1.el9_6, kernel-rt-debug-core 5.14.0-570.138.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-295-16 updated cvss 8.1

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
24d ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
CNA 3.1 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H

Affected products

  • Linux Linux
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.