CVE-2025-38192
Description
In the Linux kernel, the following vulnerability has been resolved: net: clear the dst when changing skb protocol A not-so-careful NAT46 BPF program can crash the kernel if it indiscriminately flips ingress packets from v4 to v6: BUG: kernel NULL pointer dereference, address: 0000000000000000 ip6_rcv_core (net/ipv6/ip6_input.c:190:20) ipv6_rcv (net/ipv6/ip6_input.c:306:8) process_backlog (net/core/dev.c:6186:4) napi_poll (net/core/dev.c:6906:9) net_rx_action (net/core/dev.c:7028:13) do_softirq (kernel/softirq.c:462:3) netif_rx (net/core/dev.c:5326:3) dev_loopback_xmit (net/core/dev.c:4015:2) ip_mc_finish_output (net/ipv4/ip_output.c:363:8) NF_HOOK (./include/linux/netfilter.h:314:9) ip_mc_output (net/ipv4/ip_output.c:400:5) dst_output (./include/net/dst.h:459:9) ip_local_out (net/ipv4/ip_output.c:130:9) ip_send_skb (net/ipv4/ip_output.c:1496:8) udp_send_skb (net/ipv4/udp.c:1040:8) udp_sendmsg (net/ipv4/udp.c:1328:10) The output interface has a 4->6 program attached at ingress. We try to loop the multicast skb back to the sending socket. Ingress BPF runs as part of netif_rx(), pushes a valid v6 hdr and changes skb->protocol to v6. We enter ip6_rcv_core which tries to use skb_dst(). But the dst is still an IPv4 one left after IPv4 mcast output. Clear the dst in all BPF helpers which change the protocol. Try to preserve metadata dsts, those may carry non-routing metadata.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 6.16 | Affected | — |
| — | Affected | 6.6.95 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.35-1 |
| sid | Fixed | 6.12.35-1 |
| forky | Fixed | 6.12.35-1 |
| bullseye | Fixed | 6.1.170-1~deb11u1 |
| bookworm | Fixed | 6.1.170-1 |
References
- https://www.suse.com/security/cve/CVE-2025-38192.html
- https://security-tracker.debian.org/tracker/CVE-2025-38192
- https://git.kernel.org/stable/c/2a3ad42a57b43145839f2f233fb562247658a6d9
- https://git.kernel.org/stable/c/98b1d8dc9a3170b2614f1e8c93854e75cdd83980
- https://git.kernel.org/stable/c/a046f183d21ab5ace5a96ece4cf9873a42f003a7
- https://git.kernel.org/stable/c/ba9db6f907ac02215e30128770f85fbd7db2fcf9
- https://git.kernel.org/stable/c/bfa4d86e130a09f67607482e988313430e38f6c4
- https://git.kernel.org/stable/c/e9994e7b9f7bbb882d13c8191731649249150d21
CWEs
CWE-476
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.