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Linux Kernel EUVDEUVD-2026-64374

| CVE-2026-74687 HIGH
2026-08-22 Linux GHSA-x3hg-mqqh-m29v
7.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
6.4 MEDIUM

Race condition timing requires AC:H; triggering driver unload requires CAP_SYS_MODULE, so PR:H; kernel UAF yields full CIA:H.

3.1 AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

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

Lifecycle Timeline

5
Analysis Generated
Aug 25, 2026 - 07:12 vuln.today
CVSS changed
Aug 25, 2026 - 06:22 NVD
7.8 (HIGH)
Patch available
Aug 22, 2026 - 16:01 EUVD
CVE Published
Aug 22, 2026 - 15:32 cve.org
HIGH 7.8
CVE Published
Aug 22, 2026 - 15:32 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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

watchdog: at91sam9_wdt: prevent timer rearm during teardown

at91_ping() rearms the watchdog timer from its callback. timer_delete() neither waits for a running callback nor prevents it from rearming the timer, so probe failure or driver removal can leave the timer accessing the devm-allocated at91wdt after it has been freed.

Use timer_shutdown_sync() on both teardown paths. It waits for a running callback and rejects any attempt by the callback to rearm the timer.

AnalysisAI

Use-after-free race condition in the Linux kernel at91sam9_wdt watchdog driver allows a local attacker with low privileges on affected AT91 SAM9 SoC hardware to corrupt freed memory, potentially achieving kernel-level code execution. The flaw arises because at91_ping() rearms a kernel timer from within its own callback, while timer_delete() neither waits for an in-flight callback to finish nor prevents rearming - leaving a window during probe failure or driver removal where the timer accesses devm-allocated memory that has already been freed. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Gain local access to AT91 SAM9 Linux system
Delivery
Trigger at91sam9_wdt driver removal or probe failure
Exploit
Race timer callback against devm memory release
Execution
Timer callback accesses freed at91wdt memory
Persist
Corrupt kernel heap via use-after-free
Impact
Escalate privileges to root

Vulnerability AssessmentAI

Exploitation Exploitation requires physical or logical access to a Linux system running on AT91 SAM9 SoC hardware with the at91sam9_wdt watchdog driver loaded - this driver is not present or active on any other hardware platform. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) rates this as High severity, reflecting the full CIA impact achievable from a kernel use-after-free. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker with local access on an embedded Linux system based on an Atmel/Microchip AT91 SAM9 SoC - such as an industrial controller or IoT gateway - triggers watchdog driver removal (e.g., via rmmod at91sam9_wdt on a system where this is permitted, or by inducing probe failure at boot). If the at91_ping() timer callback fires in the narrow window between devm memory release and timer cancellation, the callback writes into freed memory, potentially corrupting kernel heap structures. …
Remediation The primary fix is to upgrade to a patched Linux kernel stable release: 6.18.45 or later on the 6.18.x branch, 7.1.9 or later on the 7.1.x branch, or 7.2 (mainline). … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, verify whether your organization uses AT91 SAM9 SoC hardware by querying hardware inventory and consulting infrastructure teams. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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EUVD-2026-64374 vulnerability details – vuln.today

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