Bug 2540357 (CVE-2026-93263)

Summary:	CVE-2026-93263 kernel: clk: eswin: Zero-initialize stack-allocated clk_init_data
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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 ESWIN clock driver. Due to uninitialized stack memory during clock registration, leftover data can cause the clock framework to dereference an invalid pointer. This issue can trigger a kernel crash during device initialization, resulting in a Denial of Service (DoS).	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 2026-09-24 16:24:03 UTC

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

clk: eswin: Zero-initialize stack-allocated clk_init_data

eswin_clk_register_pll() and eswin_register_clkdiv() declare a struct
clk_init_data on the stack and only initialize some of its fields
(parent_data respectively parent_hws). clk_core_populate_parent_map()
checks parent_names first and parent_data second before falling back
to parent_hws, so leftover stack garbage in the uninitialized fields
hijacks parent resolution and the clk core dereferences a bogus
pointer:

  Unable to handle kernel NULL pointer dereference at virtual address 000000000000000c
  Oops [#1]
  epc : __clk_register+0x31a/0x7f0
  [<ffffffff805dc774>] __clk_register+0x31a/0x7f0
  [<ffffffff805dcd76>] devm_clk_hw_register+0x2a/0x94
  [<ffffffff805e319a>] eswin_register_clkdiv+0x80/0xd0
  [<ffffffff805e34a0>] eswin_clk_register_clks+0x162/0x1a0
  [<ffffffff805e3736>] eic7700_clk_probe+0x146/0x180
  [<ffffffff8065d23c>] platform_probe+0x3c/0x7a

Observed on EIC7700 hardware (with the driver backported to a 6.17
tree); whether the bug triggers depends entirely on what the stack
happens to contain when the registration helpers run.

Zero-initialize both structures.

Comment 1 gkamathe 2026-09-28 11:19:34 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93263.mbox