CVE-2026-31538
Published: April 24, 2026· Updated: Apr 28, 2026
Official Description
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.
Technical Analysis
CVE-2026-31538 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (3)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-31538 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts