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Fencer Vulns
no cvss —

CVE-2026-93226 json

ipv6: use RCU iterator to dump route exceptions

published 2026-09-24 46 d ago modified 2026-10-19 21 d ago also EUVD-2026-86231

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

ipv6: use RCU iterator to dump route exceptions

rt6_nh_dump_exceptions() uses hlist_for_each_entry() to iterate over RCU-protected exception lists. The caller holds rcu_read_lock(), but does not hold rt6_exception_lock, so rt6_insert_exception() can concurrently add an entry with hlist_add_head_rcu().

KCSAN reports this race (irrelevant details omitted):

================================================================== BUG: KCSAN: data-race in rt6_insert_exception / rt6_nh_dump_exceptions

write (marked) to 0xffff8a7c44c59620 of 8 bytes by interrupt on cpu 5: rt6_insert_exception+0x3bb/0x760 __ip6_rt_update_pmtu+0x4fe/0x750 ip6_sk_update_pmtu+0x19a/0x3b0 udpv6_err+0x3ff/0x800 icmpv6_notify+0x1e1/0x440 icmpv6_rcv+0x8c0/0xab0 ip6_protocol_deliver_rcu+0x616/0x840 ip6_input_finish+0xb9/0x160 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8a7c44c59620 of 8 bytes by task 549 on cpu 14: rt6_nh_dump_exceptions+0xb3/0x260 rt6_dump_route+0x53e/0x5f0 fib6_dump_node+0x6d/0xf0 fib6_walk_continue+0x290/0x2d0 fib6_dump_table+0x28d/0x360 inet6_dump_fib+0x37d/0x620 rtnl_dumpit+0x7b/0xd0 netlink_dump+0x3ae/0x7e0 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f

4 locks held by dumper/549: ... #1: (rcu_read_lock){....}-{1:3}, at: inet6_dump_fib+0x88/0x620 #2: (&tb->tb6_lock){+.-.}-{3:3}, at: fib6_dump_table+0x1e9/0x360 #3: (rcu_read_lock){....}-{1:3}, at: rt6_dump_route+0x483/0x5f0

value changed: 0xffff8a7c44e05700 -> 0xffff8a7c45d60100

Reported by Kernel Concurrency Sanitizer on: CPU: 14 UID: 0 PID: 549 Comm: dumper Not tainted 7.2.0-rc7-virtme #38 PREEMPT(lazy) ...

Use hlist_for_each_entry_rcu() to safely iterate over the exception list.

Patch / fix

  • Linux Linux 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-93226

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-93226

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-source openSUSE Tumbleweed 7.2.8-1.1

opensuse advisories openSUSE-SU-2026:11893-1

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-2026-93226 updated cvss 5.5

kernel: ipv6: use RCU iterator to dump route exceptions

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    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

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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