cbcvebase.
CVE-2026-23398
published 2026-03-26

CVE-2026-23398: In the Linux kernel, the following vulnerability has been resolved: icmp: fix NULL pointer dereference in icmp_tag_validation() icmp_tag_validation()…

PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.12%
2.1th percentile
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: 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) 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.

Affected

69 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.19.10-1 (forky)linux 6.19.10-1 (forky)
linuxlinux
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < 571d9d7b650f02d1e38c01128817868bceac9edd571d9d7b650f02d1e38c01128817868bceac9edd
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < d783fa413c702ff0f8f8bea63f862e28eeaf39e3d783fa413c702ff0f8f8bea63f862e28eeaf39e3
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < 1f9f2c6d4b2a613b7756fc5679c5116ba2ca01611f9f2c6d4b2a613b7756fc5679c5116ba2ca0161
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < b61529c357f1ee4d64836eb142a542d2e7ad67ceb61529c357f1ee4d64836eb142a542d2e7ad67ce
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < 9647e99d2a617c355d2b378be0ff6d0e848fd5799647e99d2a617c355d2b378be0ff6d0e848fd579
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < d938dd5a0ad780c891ea3bc94cae7405f11e618ad938dd5a0ad780c891ea3bc94cae7405f11e618a
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < 1e4e2f5e48cec0cccaea9815fb9486c084ba41e21e4e2f5e48cec0cccaea9815fb9486c084ba41e2
linuxlinux>= 8ed1dc44d3e9e8387a104b1ae8f92e9a3fbf1b1e < 614aefe56af8e13331e50220c936fc0689cf5675614aefe56af8e13331e50220c936fc0689cf5675
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.19.10-16.19.10-1
linuxlinux_kernel>= 3.14.0 < 6.1.1676.1.167
linuxlinux_kernel>= 3.14.1 < 5.10.2535.10.253
linuxlinux_kernel>= 5.11 < 5.15.2035.15.203
linuxlinux_kernel>= 5.16 < 6.1.1676.1.167
linuxlinux_kernel>= 6.13 < 6.18.206.18.20
linuxlinux_kernel>= 6.13.0 < 6.18.206.18.20

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_ubuntu7.1HIGH
vendor_msrc6.5MEDIUM
vendor_redhat6.2MEDIUM
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