CVE-2026-23381

Description

In the Linux kernel, the following vulnerability has been resolved:net: bridge: fix nd_tbl null dereference when IPv6 is disabledWhen booting with the ipv6.disable=1 parameter, the nd_tbl is neverinitialized because inet6_init() exits before ndisc_init() is calledwhich initializes it. Then, if neigh_suppress is enabled and an ICMPv6Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() willdereference ipv6_stub->nd_tbl which is null, passing it toneigh_lookup(). This causes a kernel null pointer dereference. BUG: kernel null pointer dereference, address: 0000000000000268 Oops: 0000 [#1] PREEMPT SMP NOPTI [...] RIP: 0010:neigh_lookup+0x16/0xe0 [...] Call Trace: neigh_lookup+0x16/0xe0 br_do_suppress_nd+0x160/0x290 [bridge] br_handle_frame_finish+0x500/0x620 [bridge] br_handle_frame+0x353/0x440 [bridge] __netif_receive_skb_core.constprop.0+0x298/0x1110 __netif_receive_skb_one_core+0x3d/0xa0 process_backlog+0xa0/0x140 __napi_poll+0x2c/0x170 net_rx_action+0x2c4/0x3a0 handle_softirqs+0xd0/0x270 do_softirq+0x3f/0x60Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() inthe callers. This is in essence disabling NS/NA suppression when IPv6 isdisabled.

Risk Information

Base Score

5.5

MODERATE

Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Score

Exploitation Probability

0.032

Associated Vulnerability

No records found

Patch Details

No records found

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234