{"id":"CVE-2026-23304","summary":"ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()\n\nl3mdev_master_dev_rcu() can return NULL when the slave device is being\nun-slaved from a VRF. All other callers deal with this, but we lost\nthe fallback to loopback in ip6_rt_pcpu_alloc() -\u003e ip6_rt_get_dev_rcu()\nwith commit 4832c30d5458 (\"net: ipv6: put host and anycast routes on\ndevice with address\").\n\n  KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f]\n  RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418)\n  Call Trace:\n   ip6_pol_route (net/ipv6/route.c:2318)\n   fib6_rule_lookup (net/ipv6/fib6_rules.c:115)\n   ip6_route_output_flags (net/ipv6/route.c:2607)\n   vrf_process_v6_outbound (drivers/net/vrf.c:437)\n\nI was tempted to rework the un-slaving code to clear the flag first\nand insert synchronize_rcu() before we remove the upper. But looks like\nthe explicit fallback to loopback_dev is an established pattern.\nAnd I guess avoiding the synchronize_rcu() is nice, too.","modified":"2026-04-02T13:12:20.783222Z","published":"2026-03-25T10:26:59.015Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23304.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0b5a7826020706057cc5a9d9009e667027f221ee"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3310fc11fc47387d1dd4759b0bc961643ea11c7f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4a48fe59f29f673a3d042d679f26629a9c3e29d4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/581800298313c9fd75e94985e6d37d21b7e35d34"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ae88c8256547b63980770a9ea7be73a15900d27e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23304.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23304"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4832c30d5458387ff2533ff66fbde26ad8bb5a2d"},{"fixed":"4a48fe59f29f673a3d042d679f26629a9c3e29d4"},{"fixed":"581800298313c9fd75e94985e6d37d21b7e35d34"},{"fixed":"3310fc11fc47387d1dd4759b0bc961643ea11c7f"},{"fixed":"0b5a7826020706057cc5a9d9009e667027f221ee"},{"fixed":"ae88c8256547b63980770a9ea7be73a15900d27e"},{"fixed":"2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23304.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.14.0"},{"fixed":"6.1.167"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.77"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.17"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23304.json"}}],"schema_version":"1.7.5"}