Bug 2492776 (CVE-2026-53188)

Summary:	CVE-2026-53188 kernel: RDMA/core: Validate the passed in fops for ib_get_ucaps()
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 RDMA/core component. This vulnerability arises from insufficient validation of file operations (fops) passed to the ib_get_ucaps() function. A local attacker could exploit this by creating a block device with a device number (dev_t) that aliases a character device (char/block alias), allowing them to masquerade as a legitimate user capabilities (ucap) character device file descriptor. This impersonation could lead to a security bypass, potentially granting unauthorized access to RDMA capabilities.	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 2026-06-25 10:05:07 UTC

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

RDMA/core: Validate the passed in fops for ib_get_ucaps()

Sashiko pointed out it is not safe to rely only on the devt because
char/block alias so if the user finds a block device with the same dev_t
it can masquerade as a ucap cdev fd.

Test the f_ops to only accept authentic cdevs.

Comment 1 TEJ RATHI 2026-06-26 08:43:30 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062557-CVE-2026-53188-8d3d@gregkh/T