🛡️ CVE-2026-68425 — kernel

IB/mad: Drop unmatched RMPP responses before reassembly

In the Linux kernel, the following vulnerability has been resolved:

IB/mad: Drop unmatched RMPP responses before reassembly

Kernel-handled RMPP receive processing starts reassembly for active

DATA responses before the response is matched to an outstanding send.

The normal match happens later, after ib_process_rmpp_recv_wc() has

either assembled a complete message or consumed the segment.

That ordering lets an unsolicited response that routes to a kernel

RMPP agent by the high TID bits allocate or extend RMPP receive state

before the full TID and source address are checked against a real

request. A reordered burst can therefore reach the receive-side

insertion path even though the response would not match any send.

For kernel-handled RMPP DATA responses, require the existing

ib_find_send_mad() match before entering RMPP reassembly. The matcher

already checks the full TID, management class and source address/GID

against the agent wait, backlog and in-flight send lists. If there is

no match, drop the response without creating RMPP state.

This leaves the RMPP window behavior unchanged and only rejects

responses that have no corresponding request.