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Linux Kernel CVE-2026-46257

| EUVDEUVD-2026-34119 MEDIUM
Use of Uninitialized Resource (CWE-908)
2026-06-03 Linux GHSA-w9qv-v668-q8rf
Information Disclosure Linux Red Hat Suse
5.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SUSE
MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

5
Analysis Generated
Jun 09, 2026 - 20:27 vuln.today
CVSS changed
Jun 09, 2026 - 20:22 NVD
5.5 (MEDIUM)
Patch available
Jun 03, 2026 - 19:01 EUVD
CVE Published
Jun 03, 2026 - 15:49 nvd
MEDIUM 5.5
CVE Published
Jun 03, 2026 - 15:49 nvd
UNKNOWN (no severity yet)

DescriptionCVE.org

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

clocksource/drivers/timer-sp804: Fix an Oops when read_current_timer is called on ARM32 platforms where the SP804 is not registered as the sched_clock.

On SP804, the delay timer shares the same clkevt instance with sched_clock. On some platforms, when sp804_clocksource_and_sched_clock_init is called with use_sched_clock not set to 1, sched_clkevt is not properly initialized. However, sp804_register_delay_timer is invoked unconditionally, and read_current_timer() subsequently calls sp804_read on an uninitialized sched_clkevt, leading to a kernel Oops when accessing sched_clkevt->value.

Declare a dedicated clkevt instance exclusively for delay timer, instead of sharing the same clkevt with sched_clock. This ensures that read_current_timer continues to work correctly regardless of whether SP804 is selected as the sched_clock.

AnalysisAI

Local denial-of-service via kernel Oops in the Linux kernel SP804 timer driver on ARM32 platforms when read_current_timer() dereferences an uninitialized sched_clkevt pointer. Affected systems are those where sp804_clocksource_and_sched_clock_init is invoked without use_sched_clock=1, yet sp804_register_delay_timer is still called unconditionally - creating the conditions for a NULL/uninitialized pointer access in sp804_read(). EPSS is 0.02% (5th percentile), no KEV listing exists, and no public exploit has been identified, placing this as low operational priority outside specialized ARM32 embedded deployments.

Technical ContextAI

The SP804 is a dual-channel ARM timer IP block present in SoCs based on ARM Versatile, RealView, and related platforms, implemented in the Linux kernel at drivers/clocksource/timer-sp804.c. Prior to the fix, the delay timer and sched_clock subsystem shared a single clkevt instance (sched_clkevt). When sp804_clocksource_and_sched_clock_init() is called with use_sched_clock=0 - meaning SP804 is not chosen as the platform scheduler clock - sched_clkevt is never initialized. Despite this, sp804_register_delay_timer() is unconditionally registered, and a subsequent call to read_current_timer() invokes sp804_read(), which accesses sched_clkevt->value on the uninitialized instance, triggering a kernel panic (Oops). This is a textbook instance of CWE-908 (Use of Uninitialized Resource). The fix resolves the issue by declaring a dedicated clkevt instance exclusively for the delay timer, decoupling it from the sched_clock path entirely. The affected CPE is cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*.

RemediationAI

The primary fix is upgrading to Linux kernel 6.19.4 (stable) or 7.0 (mainline), both of which introduce a dedicated clkevt instance for the SP804 delay timer, eliminating the uninitialized resource dereference. The stable-branch fix commit is available at https://git.kernel.org/stable/c/693b0b594b0f278bafa784984129c0c0f988e352 and the mainline fix at https://git.kernel.org/stable/c/694921a93f3e3621e067afc545cedf6fe3b234a9. Distributions shipping ARM32 kernel builds should backport these commits to their supported kernel versions. For systems that cannot be immediately updated, a compensating control is to modify the platform's board file or device tree to set use_sched_clock=1 for the SP804 instance if the hardware supports it, which prevents the uninitialized path from being reached - though this may alter timer scheduling behavior and should be validated on the specific platform. Alternatively, disabling the SP804 delay timer registration via kernel configuration (CONFIG_ARM_SP804) eliminates the vulnerable code path at the cost of delay timer functionality. NVD advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-46257.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 Not-Affected

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CVE-2026-46257 vulnerability details – vuln.today
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