CVE-2024-44931

What it actually does

Userspace ioctl calls with an out-of-range offset allow an unsanitized array index into the gpio descriptor array, enabling speculative reads outside the intended bounds and potential information disclosure via side channels.

Why it matters to the business

Low-probability kernel memory disclosure could expose sensitive data to local attackers on systems running affected kernels or Android Bluetooth stacks; urgency remains low given absent KEV listing, ransomware use, and flat EPSS trend over 777 days since publication.

How an attack unfolds

An attacker invokes gpio_ioctl() from userspace with a deliberately out-of-bounds offset; the kernel uses the value as an array index without sanitization, permitting speculative execution to read arbitrary kernel memory. Information is then leaked through cache-timing side channels. Listed threat actors reference generic Linux kernel out-of-bounds and uninitialized-resource campaigns rather than confirmed exploitation of this specific issue.

How to fix it

Apply the upstream fix that introduces array_index_nospec() sanitization (Linux commit 18504710442671b02d00e6db9804a0ad26c5a479) or the corresponding Android Bluetooth patches released for versions 10/11/12/13 on 2022-12-01. Rebuild and deploy updated kernels or system images; verify the mitigation is present in gpio_device_get_desc().

How to confirm the fix worked

Confirm the presence of array_index_nospec() around the offset usage in gpio_device_get_desc() via source inspection or kernel binary diff; test that out-of-range gpio ioctl offsets no longer produce observable speculative reads; monitor for updated package versions matching the listed fixed commits.

Typical attack path

1. Obtain local unprivileged access on a vulnerable Linux or Android system
2. Locate a gpio character device and open it
3. Craft and issue an ioctl command supplying an offset beyond the descriptor array bounds
4. Measure cache timing or other microarchitectural artifacts to recover speculatively read kernel data
5. Repeat or refine to exfiltrate targeted memory contents

How to detect it

Exploitation leaves no reliable post-facto artifacts because the flaw is speculative; monitor for repeated gpio ioctl calls with abnormal offsets in kernel or audit logs, and watch for unusual cache or performance-counter activity on gpio devices. Correlate with any listed generic Linux kernel out-of-bounds campaigns if threat intelligence indicates active targeting.

What your security team should do

• Prioritize patching production kernels and Android devices to the cited fixed commits within standard maintenance windows
• Review local code or drivers performing similar unsanitized user-to-array-index operations for analogous speculation issues
• Update kernel and Android build pipelines to include static-analysis checks equivalent to the Coverity finding that discovered this flaw