CVE-2026-23398
Description
In the Linux kernel, the following vulnerability has been resolved:
icmp: fix NULL pointer dereference in icmp_tag_validation()
icmp_tag_validation() unconditionally dereferences the result of
rcu_dereference(inet_protos[proto]) without checking for NULL.
The inet_protos[] array is sparse -- only about 15 of 256 protocol
numbers have registered handlers. When ip_no_pmtu_disc is set to 3
(hardened PMTU mode) and the kernel receives an ICMP Fragmentation
Needed error with a quoted inner IP header containing an unregistered
protocol number, the NULL dereference causes a kernel panic in
softirq context.
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
RIP: 0010:icmp_unreach (net/ipv4/icmp.c:1085 net/ipv4/icmp.c:1143)
Call Trace:
<IRQ>
icmp_rcv (net/ipv4/icmp.c:1527)
ip_protocol_deliver_rcu (net/ipv4/ip_input.c:207)
ip_local_deliver_finish (net/ipv4/ip_input.c:242)
ip_local_deliver (net/ipv4/ip_input.c:262)
ip_rcv (net/ipv4/ip_input.c:573)
__netif_receive_skb_one_core (net/core/dev.c:6164)
process_backlog (net/core/dev.c:6628)
handle_softirqs (kernel/softirq.c:561)
</IRQ>
Add a NULL check before accessing icmp_strict_tag_validation. If the
protocol has no registered handler, return false since it cannot
perform strict tag validation.
EPSS (Exploit Prediction Scoring System)
EPSS (Exploit Prediction Scoring System)
Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.