# CVE-2026-31538: linux: In the Linux kernel, the following vulnerability has been resolved:  smb: server: make use of smbdirect_socket.recv_i...

CVE-2026-31538 is fixed in linux on 1 platform by DEBIAN-CVE-2026-31538 (version 6.18.12-1), released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-31538
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 24, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.12-1 | [DEBIAN-CVE-2026-31538](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31538.md) | May 15, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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