In the Linux kernel, the following vulnerability has been resolved:
udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n
When CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0
(success) without actually creating a socket. Callers such as
fou_create() then proceed to dereference the uninitialized socket
pointer, resulting in a NULL pointer dereference.
The captured NULL deref crash:
BUG: kernel NULL pointer dereference, address: 0000000000000018
RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)
[...]
Call Trace:
<TASK>
genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)
genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)
[...]
netlink_rcv_skb (net/netlink/af_netlink.c:2550)
genl_rcv (net/netlink/genetlink.c:1219)
netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
netlink_sendmsg (net/netlink/af_netlink.c:1894)
__sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))
__sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))
__x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)
This patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so
callers correctly take their error paths. There is only one caller of
the vulnerable function and only privileged users can trigger it.
References
Configurations
Configuration 1 (hide)
|
History
23 Apr 2026, 20:59
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/003343985f26dfefd0c94b1fe1316a2de74428b9 - Patch | |
| References | () https://git.kernel.org/stable/c/12aa4b73a67d95bc739995a2d6943aec2f9785c9 - Patch | |
| References | () https://git.kernel.org/stable/c/66117dbb3dbae82f86735bf727b1d59cc677afa1 - Patch | |
| References | () https://git.kernel.org/stable/c/9f036aa0fe46c19e938f03d10e02c23f4fffae5e - Patch | |
| References | () https://git.kernel.org/stable/c/a05a2149386f6dfb4245f522acdbef892acafc84 - Patch | |
| References | () https://git.kernel.org/stable/c/b3a6df291fecf5f8a308953b65ca72b7fc9e015d - Patch | |
| References | () https://git.kernel.org/stable/c/ba7c9ddcdd077942b798979edb035207374d4096 - Patch | |
| References | () https://git.kernel.org/stable/c/dfc96ae0074cc47b5478a59e5aa19233e434243f - Patch | |
| CWE | CWE-476 | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux
Linux linux Kernel |
|
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:3.18:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
18 Apr 2026, 09:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
03 Apr 2026, 16:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-03 16:16
Updated : 2026-04-23 20:59
NVD link : CVE-2026-23439
Mitre link : CVE-2026-23439
CVE.ORG link : CVE-2026-23439
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-476
NULL Pointer Dereference