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net: clear the dst when changing skb protocol (Linux Linux)

CVE-2025-38192
HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.20 % · percentile 10 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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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.

Weaknesses (CWE)

  • CWE-476 — NULL Pointer Dereference

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 6578171a7ff0c31dc73258f93da7407510abf085 < a046f183d21ab5ace5a96ece4cf9873a42f003a7 ; affected 6578171a7ff0c31dc73258f93da7407510abf085 < 98b1d8dc9a3170b2614f1e8c93854e75cdd83980 ; affected 6578171a7ff0c31dc73258f93da7407510abf085 < bfa4d86e130a09f67607482e988313430e38f6c4 ; affected 6578171a7ff0c31dc73258f93da7407510abf085 < 2a3ad42a57b43145839f2f233fb562247658a6d9 ; affected 6578171a7ff0c31dc73258f93da7407510abf085 < e9994e7b9f7bbb882d13c8191731649249150d21 ; affected 6578171a7ff0c31dc73258f93da7407510abf085 < ba9db6f907ac02215e30128770f85fbd7db2fcf9
Linux · Linuxaffected 4.8 ; unaffected 0 < 4.8 ; unaffected 5.15.209 ≤ 5.15.* ; unaffected 6.1.167 ≤ 6.1.* ; unaffected 6.6.95 ≤ 6.6.* ; unaffected 6.12.35 ≤ 6.12.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD