{"id":"AZL-64710","summary":"CVE-2025-38192 affecting package kernel for versions less than 6.6.96.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: clear the dst when changing skb protocol\n\nA not-so-careful NAT46 BPF program can crash the kernel\nif it indiscriminately flips ingress packets from v4 to v6:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n    ip6_rcv_core (net/ipv6/ip6_input.c:190:20)\n    ipv6_rcv (net/ipv6/ip6_input.c:306:8)\n    process_backlog (net/core/dev.c:6186:4)\n    napi_poll (net/core/dev.c:6906:9)\n    net_rx_action (net/core/dev.c:7028:13)\n    do_softirq (kernel/softirq.c:462:3)\n    netif_rx (net/core/dev.c:5326:3)\n    dev_loopback_xmit (net/core/dev.c:4015:2)\n    ip_mc_finish_output (net/ipv4/ip_output.c:363:8)\n    NF_HOOK (./include/linux/netfilter.h:314:9)\n    ip_mc_output (net/ipv4/ip_output.c:400:5)\n    dst_output (./include/net/dst.h:459:9)\n    ip_local_out (net/ipv4/ip_output.c:130:9)\n    ip_send_skb (net/ipv4/ip_output.c:1496:8)\n    udp_send_skb (net/ipv4/udp.c:1040:8)\n    udp_sendmsg (net/ipv4/udp.c:1328:10)\n\nThe output interface has a 4-\u003e6 program attached at ingress.\nWe try to loop the multicast skb back to the sending socket.\nIngress BPF runs as part of netif_rx(), pushes a valid v6 hdr\nand changes skb-\u003eprotocol to v6. We enter ip6_rcv_core which\ntries to use skb_dst(). But the dst is still an IPv4 one left\nafter IPv4 mcast output.\n\nClear the dst in all BPF helpers which change the protocol.\nTry to preserve metadata dsts, those may carry non-routing\nmetadata.","modified":"2026-04-01T05:20:23.319088Z","published":"2025-07-04T14:15:26Z","upstream":["CVE-2025-38192"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38192"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.96.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-64710.json"}}],"schema_version":"1.7.5"}