{"api_version":"1","generated_at":"2026-04-19T01:13:11+00:00","cve":"CVE-2026-23439","urls":{"html":"https://cve.report/CVE-2026-23439","api":"https://cve.report/api/cve/CVE-2026-23439.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-23439","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-23439"},"summary":{"title":"udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nudp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n\n\nWhen CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0\n(success) without actually creating a socket. Callers such as\nfou_create() then proceed to dereference the uninitialized socket\npointer, resulting in a NULL pointer dereference.\n\nThe captured NULL deref crash:\n  BUG: kernel NULL pointer dereference, address: 0000000000000018\n  RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)\n  [...]\n  Call Trace:\n    <TASK>\n    genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)\n    genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)\n    [...]\n    netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n    genl_rcv (net/netlink/genetlink.c:1219)\n    netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\n    netlink_sendmsg (net/netlink/af_netlink.c:1894)\n    __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))\n    __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))\n    __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))\n    do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\n    entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)\n\nThis patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so\ncallers correctly take their error paths. There is only one caller of\nthe vulnerable function and only privileged users can trigger it.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-03 16:16:25","updated_at":"2026-04-18 09:16:26"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b3a6df291fecf5f8a308953b65ca72b7fc9e015d","name":"https://git.kernel.org/stable/c/b3a6df291fecf5f8a308953b65ca72b7fc9e015d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dfc96ae0074cc47b5478a59e5aa19233e434243f","name":"https://git.kernel.org/stable/c/dfc96ae0074cc47b5478a59e5aa19233e434243f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9f036aa0fe46c19e938f03d10e02c23f4fffae5e","name":"https://git.kernel.org/stable/c/9f036aa0fe46c19e938f03d10e02c23f4fffae5e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ba7c9ddcdd077942b798979edb035207374d4096","name":"https://git.kernel.org/stable/c/ba7c9ddcdd077942b798979edb035207374d4096","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/003343985f26dfefd0c94b1fe1316a2de74428b9","name":"https://git.kernel.org/stable/c/003343985f26dfefd0c94b1fe1316a2de74428b9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/12aa4b73a67d95bc739995a2d6943aec2f9785c9","name":"https://git.kernel.org/stable/c/12aa4b73a67d95bc739995a2d6943aec2f9785c9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a05a2149386f6dfb4245f522acdbef892acafc84","name":"https://git.kernel.org/stable/c/a05a2149386f6dfb4245f522acdbef892acafc84","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/66117dbb3dbae82f86735bf727b1d59cc677afa1","name":"https://git.kernel.org/stable/c/66117dbb3dbae82f86735bf727b1d59cc677afa1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-23439","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23439","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 dfc96ae0074cc47b5478a59e5aa19233e434243f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 66117dbb3dbae82f86735bf727b1d59cc677afa1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 ba7c9ddcdd077942b798979edb035207374d4096 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 a05a2149386f6dfb4245f522acdbef892acafc84 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 9f036aa0fe46c19e938f03d10e02c23f4fffae5e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 003343985f26dfefd0c94b1fe1316a2de74428b9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 12aa4b73a67d95bc739995a2d6943aec2f9785c9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fd384412e199b62c3ddaabd18dce86d0e164c5b9 b3a6df291fecf5f8a308953b65ca72b7fc9e015d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.253 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.203 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.167 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.130 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.78 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.20 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.10 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"23439","cve":"CVE-2026-23439","epss":"0.000320000","percentile":"0.090980000","score_date":"2026-04-18","updated_at":"2026-04-19 00:10:43"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/net/udp_tunnel.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"dfc96ae0074cc47b5478a59e5aa19233e434243f","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"66117dbb3dbae82f86735bf727b1d59cc677afa1","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"ba7c9ddcdd077942b798979edb035207374d4096","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"a05a2149386f6dfb4245f522acdbef892acafc84","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"9f036aa0fe46c19e938f03d10e02c23f4fffae5e","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"003343985f26dfefd0c94b1fe1316a2de74428b9","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"12aa4b73a67d95bc739995a2d6943aec2f9785c9","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"},{"lessThan":"b3a6df291fecf5f8a308953b65ca72b7fc9e015d","status":"affected","version":"fd384412e199b62c3ddaabd18dce86d0e164c5b9","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/udp_tunnel.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.18"},{"lessThan":"3.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.253","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.203","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.167","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.130","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.78","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.20","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.253","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.203","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.167","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.130","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.78","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.20","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.10","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"3.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nudp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n\n\nWhen CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0\n(success) without actually creating a socket. Callers such as\nfou_create() then proceed to dereference the uninitialized socket\npointer, resulting in a NULL pointer dereference.\n\nThe captured NULL deref crash:\n  BUG: kernel NULL pointer dereference, address: 0000000000000018\n  RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)\n  [...]\n  Call Trace:\n    <TASK>\n    genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)\n    genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)\n    [...]\n    netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n    genl_rcv (net/netlink/genetlink.c:1219)\n    netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\n    netlink_sendmsg (net/netlink/af_netlink.c:1894)\n    __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))\n    __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))\n    __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))\n    do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\n    entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)\n\nThis patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so\ncallers correctly take their error paths. There is only one caller of\nthe vulnerable function and only privileged users can trigger it."}],"providerMetadata":{"dateUpdated":"2026-04-18T08:58:55.464Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/dfc96ae0074cc47b5478a59e5aa19233e434243f"},{"url":"https://git.kernel.org/stable/c/66117dbb3dbae82f86735bf727b1d59cc677afa1"},{"url":"https://git.kernel.org/stable/c/ba7c9ddcdd077942b798979edb035207374d4096"},{"url":"https://git.kernel.org/stable/c/a05a2149386f6dfb4245f522acdbef892acafc84"},{"url":"https://git.kernel.org/stable/c/9f036aa0fe46c19e938f03d10e02c23f4fffae5e"},{"url":"https://git.kernel.org/stable/c/003343985f26dfefd0c94b1fe1316a2de74428b9"},{"url":"https://git.kernel.org/stable/c/12aa4b73a67d95bc739995a2d6943aec2f9785c9"},{"url":"https://git.kernel.org/stable/c/b3a6df291fecf5f8a308953b65ca72b7fc9e015d"}],"title":"udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-23439","datePublished":"2026-04-03T15:15:23.734Z","dateReserved":"2026-01-13T15:37:46.017Z","dateUpdated":"2026-04-18T08:58:55.464Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-03 16:16:25","lastModifiedDate":"2026-04-18 09:16:26","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"23439","Ordinal":"1","Title":"udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFI","CVE":"CVE-2026-23439","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"23439","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nudp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n\n\nWhen CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0\n(success) without actually creating a socket. Callers such as\nfou_create() then proceed to dereference the uninitialized socket\npointer, resulting in a NULL pointer dereference.\n\nThe captured NULL deref crash:\n  BUG: kernel NULL pointer dereference, address: 0000000000000018\n  RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)\n  [...]\n  Call Trace:\n    <TASK>\n    genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)\n    genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)\n    [...]\n    netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n    genl_rcv (net/netlink/genetlink.c:1219)\n    netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\n    netlink_sendmsg (net/netlink/af_netlink.c:1894)\n    __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))\n    __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))\n    __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))\n    do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\n    entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)\n\nThis patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so\ncallers correctly take their error paths. There is only one caller of\nthe vulnerable function and only privileged users can trigger it.","Type":"Description","Title":"udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFI"}]}}}