udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n
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: 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
CVE-2026-23439
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-23439
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "dfc96ae0074cc47b5478a59e5aa19233e434243f",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "66117dbb3dbae82f86735bf727b1d59cc677afa1",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "ba7c9ddcdd077942b798979edb035207374d4096",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "a05a2149386f6dfb4245f522acdbef892acafc84",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "9f036aa0fe46c19e938f03d10e02c23f4fffae5e",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "003343985f26dfefd0c94b1fe1316a2de74428b9",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "12aa4b73a67d95bc739995a2d6943aec2f9785c9",
"versionType": "git"
},
{
"status": "affected",
"version": "fd384412e199b62c3ddaabd18dce86d0e164c5b9",
"lessThan": "b3a6df291fecf5f8a308953b65ca72b7fc9e015d",
"versionType": "git"
}
],
"programFiles": [
"include/net/udp_tunnel.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.20",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.10",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/udp_tunnel.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-23439
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #27253 · Revision 1
- Added to Heist Feed
- Publisher date