{"id":"CVE-2025-38192","summary":"net: clear the dst when changing skb protocol","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":"2026-04-24T06:42:50.482129209Z","published":"2025-07-04T13:37:16.642Z","related":["SUSE-SU-2025:02846-1","SUSE-SU-2025:02853-1","SUSE-SU-2025:02923-1","SUSE-SU-2025:02969-1","SUSE-SU-2025:02996-1","SUSE-SU-2025:02997-1","SUSE-SU-2025:03011-1","SUSE-SU-2025:03023-1","SUSE-SU-2025:20577-1","SUSE-SU-2025:20586-1","SUSE-SU-2025:20601-1","SUSE-SU-2025:20602-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38192.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2a3ad42a57b43145839f2f233fb562247658a6d9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/98b1d8dc9a3170b2614f1e8c93854e75cdd83980"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba9db6f907ac02215e30128770f85fbd7db2fcf9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bfa4d86e130a09f67607482e988313430e38f6c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e9994e7b9f7bbb882d13c8191731649249150d21"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38192.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38192"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6578171a7ff0c31dc73258f93da7407510abf085"},{"fixed":"98b1d8dc9a3170b2614f1e8c93854e75cdd83980"},{"fixed":"bfa4d86e130a09f67607482e988313430e38f6c4"},{"fixed":"2a3ad42a57b43145839f2f233fb562247658a6d9"},{"fixed":"e9994e7b9f7bbb882d13c8191731649249150d21"},{"fixed":"ba9db6f907ac02215e30128770f85fbd7db2fcf9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-38192.json"}}],"schema_version":"1.7.5"}