CVE-2026-31538 PUBLISHED

smb: server: make use of smbdirect_socket.recv_io.credits.available

Assigner: Linux
Reserved: 09.03.2026 Published: 24.04.2026 Updated: 24.04.2026

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

smb: server: make use of smbdirect_socket.recv_io.credits.available

The logic off managing recv credits by counting posted recv_io and granted credits is racy.

That's because the peer might already consumed a credit, but between receiving the incoming recv at the hardware and processing the completion in the 'recv_done' functions we likely have a window where we grant credits, which don't really exist.

So we better have a decicated counter for the available credits, which will be incremented when we posted new recv buffers and drained when we grant the credits to the peer.

This fixes regression Namjae reported with the 6.18 release.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 89b021a72663c4d96d8a8b85272bb42d991a1c6f to 66c082e3d4651e8629a393a9e182b01eb50fb0a3 (excl.)
  • affected from 89b021a72663c4d96d8a8b85272bb42d991a1c6f to 809cbd31aa4f87a1b889532244c9cf30eb022385 (excl.)
  • affected from 89b021a72663c4d96d8a8b85272bb42d991a1c6f to 26ad87a2cfb8c1384620d1693a166ed87303046e (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.18 is affected
  • unaffected from 0 to 6.18 (excl.)
  • unaffected from 6.18.11 to 6.18.* (incl.)
  • unaffected from 6.19.1 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References