Bug 2461457 (CVE-2026-31537)

Summary:	CVE-2026-31537 kernel: smb: server: make use of smbdirect_socket.send_io.bcredits
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's Server Message Block (SMB) server. An attacker could exploit this vulnerability by triggering an immediate (empty) send operation, which would corrupt the stream of reassembled data transfer messages. This corruption could lead to data integrity issues or potentially a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-24 15:02:34 UTC

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

smb: server: make use of smbdirect_socket.send_io.bcredits

It turns out that our code will corrupt the stream of
reassabled data transfer messages when we trigger an
immendiate (empty) send.

In order to fix this we'll have a single 'batch' credit per
connection. And code getting that credit is free to use
as much messages until remaining_length reaches 0, then
the batch credit it given back and the next logical send can
happen.

Comment 1 Keith Grant 2026-04-24 16:30:03 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042434-CVE-2026-31537-6202@gregkh/T