Bug 2481958 (CVE-2026-45962)

Summary:	CVE-2026-45962 kernel: ublk: Validate SQE128 flag before accessing the cmd
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 userspace block (ublk) driver. This vulnerability allows a local attacker to cause an out-of-boundary memory access by providing a specially crafted command that bypasses the IO_URING_F_SQE128 flag check. This could lead to a system crash, resulting in a denial of service (DoS), or potentially enable information disclosure.	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 2026-05-27 15:04:18 UTC

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

ublk: Validate SQE128 flag before accessing the cmd

ublk_ctrl_cmd_dump() accesses (header *)sqe->cmd before
IO_URING_F_SQE128 flag check. This could cause out of boundary memory
access.

Move the SQE128 flag check earlier in ublk_ctrl_uring_cmd() to return
-EINVAL immediately if the flag is not set.

Comment 1 Keith Grant 2026-05-27 23:11:19 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052734-CVE-2026-45962-cd10@gregkh/T