Bug 2507035 (CVE-2026-64385)

Summary:	CVE-2026-64385 kernel: Kernel SMB client: Double-free vulnerability allows remote denial of service or privilege escalation
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability-draft	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
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) client. A double-free vulnerability exists in the SMB2_ioctl() replay path, where a response buffer can be freed twice under specific error conditions. A malicious or compromised SMB server could exploit this by sending crafted responses during an I/O control (ioctl) replay sequence. This could lead to a remote denial of service due to a kernel crash, and potentially allow for privilege escalation.	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 2026-07-25 10:01:38 UTC

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

smb: client: fix double-free in SMB2_ioctl() replay

A response-bearing attempt can return a replayable error and free its
response buffer. If SMB2_ioctl_init() fails before the next send, cleanup
retains the previous buffer type and frees that response again.

Reset response bookkeeping before each attempt to prevent the stale free.

Comment 1 Mauro Matteo Cascella 2026-07-28 15:58:25 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072526-CVE-2026-64385-80b2@gregkh/T