{"id":"CVE-2026-23304","title":"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","summary":"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 dea…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.14, < 5.10.253","linux_kernel >= 5.11, < 5.15.203","linux_kernel >= 5.16, < 6.1.167","linux_kernel >= 6.2, < 6.6.130","linux_kernel >= 6.7, < 6.12.77","linux_kernel >= 6.13, < 6.18.17","linux_kernel >= 6.19, < 6.19.7","linux_kernel = 7.0"],"patched":["linux_kernel 6.19.7"],"published":"2026-03-25","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:18:48.623","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23304","references":[{"url":"https://git.kernel.org/stable/c/0b5a7826020706057cc5a9d9009e667027f221ee","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3310fc11fc47387d1dd4759b0bc961643ea11c7f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4a48fe59f29f673a3d042d679f26629a9c3e29d4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/581800298313c9fd75e94985e6d37d21b7e35d34","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a73fe9f4ae84a239d5b2686f47a58c158aee2eb4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ae88c8256547b63980770a9ea7be73a15900d27e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d542e2ac7f9e288d49735be0775611547ca4e0ee","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00134,"epssPercentile":0.02868,"ingestedAt":"2026-09-08T15:33:26.993Z","slug":"CVE-2026-23304","body":"## Overview\n\nIn 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() -> 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.\n\n## Affected\n\n- `linux_kernel >= 4.14, < 5.10.253`\n- `linux_kernel >= 5.11, < 5.15.203`\n- `linux_kernel >= 5.16, < 6.1.167`\n- `linux_kernel >= 6.2, < 6.6.130`\n- `linux_kernel >= 6.7, < 6.12.77`\n- `linux_kernel >= 6.13, < 6.18.17`\n- `linux_kernel >= 6.19, < 6.19.7`\n- `linux_kernel = 7.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.19.7`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221655,"id":"CVE-2026-23304","ts":1792035306576,"field":"cvss","old":null,"new":"5.5"},{"seq":221654,"id":"CVE-2026-23304","ts":1792035306576,"field":"severity","old":"none","new":"medium"}]}