CVE-2026-31538
smb: server: make use of smbdirect_socket.recv_io.credits.available
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.
INFO
Published Date :
April 24, 2026, 3:16 p.m.
Last Modified :
April 28, 2026, 6:59 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the resolved version.
- Apply the provided patch for SMB server credit management.
- Ensure proper credit accounting for received I/O buffers.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-31538.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-31538 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-31538
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-31538 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-31538 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Apr. 28, 2026
Action Type Old Value New Value Added CWE NVD-CWE-Other Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 6.19.1 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.18 up to (excluding) 6.18.11 Added Reference Type kernel.org: https://git.kernel.org/stable/c/26ad87a2cfb8c1384620d1693a166ed87303046e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/66c082e3d4651e8629a393a9e182b01eb50fb0a3 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/809cbd31aa4f87a1b889532244c9cf30eb022385 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 24, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/26ad87a2cfb8c1384620d1693a166ed87303046e Added Reference https://git.kernel.org/stable/c/66c082e3d4651e8629a393a9e182b01eb50fb0a3 Added Reference https://git.kernel.org/stable/c/809cbd31aa4f87a1b889532244c9cf30eb022385