{"id":"AZL-80645","summary":"CVE-2026-23304 affecting package kernel for versions less than 6.6.130.1-1","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":"2026-08-28T17:46:29.864239179Z","published":"2026-03-25T11:16:26Z","upstream":["CVE-2026-23304"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23304"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.130.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-80645.json"}}],"schema_version":"1.9.0"}