CVE-2026-80696: Linux Kernel hwmon Driver Vulnerability

CVE-2026-80696 Overview

CVE-2026-80696 is an out-of-bounds read vulnerability in the Linux kernel's ltc4282 hardware monitoring (hwmon) driver. Coverity static analysis identified the flaw while reading the minimum alarm voltage for the VGPIO channel. The driver is missing a return statement in the code path that handles VGPIO minimum alarm voltage reads. This causes execution to fall through into code that accesses memory beyond the intended bounds. A local user with permission to interact with the hwmon sysfs interface can trigger the condition and impact kernel integrity, confidentiality, and availability.

Critical Impact
A local attacker can trigger an out-of-bounds read in the ltc4282 hwmon driver, exposing kernel memory and potentially destabilizing the system.

Affected Products

Linux kernel versions containing the ltc4282 hwmon driver prior to the referenced fix commits
Distributions shipping the vulnerable drivers/hwmon/ltc4282.c code path
Systems using the LTC4282 high-voltage current and power controller with hwmon support

Discovery Timeline

2026-08-28 - CVE-2026-80696 published to NVD
2026-08-29 - Last updated in NVD database

Technical Details for CVE-2026-80696

Vulnerability Analysis

The vulnerability resides in the ltc4282 hwmon driver, which exposes voltage, current, and power telemetry for the Analog Devices LTC4282 controller through the Linux hwmon sysfs interface. When userspace reads the minimum alarm voltage attribute for the VGPIO channel, the driver executes an incorrect code path due to a missing return statement. Control flow continues past the VGPIO handler and into logic that indexes arrays sized for the two primary voltage channels, producing an out-of-bounds access.

The out-of-bounds read exposes adjacent kernel memory to the calling process. Depending on layout, this can leak sensitive data or dereference invalid pointers, resulting in system instability or a kernel oops. Exploitation requires local access with permission to read the affected hwmon sysfs nodes.

Root Cause

The root cause is a missing return statement in the switch or conditional block that handles the VGPIO channel case when computing the minimum alarm voltage. Without the return, execution falls through to subsequent case handling that assumes a different channel index range. The resulting array indexing exceeds the allocated bounds. This is a classic control-flow oversight rather than an unsafe API misuse [CWE-125].

Attack Vector

Exploitation requires local access on a system where the ltc4282 driver is loaded and its hwmon interface is exposed to the attacker. An unprivileged or low-privileged user reads the affected sysfs attribute under /sys/class/hwmon/hwmonX/. The read triggers the fall-through path and the out-of-bounds access. No user interaction beyond the sysfs read is required, and no network access is needed.

No verified public exploit code is available. Technical details of the fix are documented in the upstream commits referenced by the NVD entry, including Kernel Git Commit 00feb1c and Kernel Git Commit a0668ac.

Detection Methods for CVE-2026-80696

Indicators of Compromise

Kernel oops or panic messages referencing ltc4282 functions in dmesg or /var/log/kern.log
Unexpected KASAN: out-of-bounds reports in kernel logs when the ltc4282 driver is loaded
Repeated userspace reads against in_lcrit_alarm or related VGPIO attributes under /sys/class/hwmon/

Detection Strategies

Enumerate loaded kernel modules with lsmod | grep ltc4282 to identify systems exposing the driver
Compare the running kernel version and vendor backport state against the upstream fix commits listed in the NVD advisory
Enable KASAN in test environments to surface out-of-bounds reads against hwmon attributes during validation

Monitoring Recommendations

Forward kernel logs to a central SIEM and alert on ltc4282 oops, WARN, or KASAN entries
Monitor low-privileged process access patterns to /sys/class/hwmon/* for anomalous read activity
Track kernel package update status across fleet inventory to confirm remediation coverage

How to Mitigate CVE-2026-80696

Immediate Actions Required

Apply the stable kernel update that includes the upstream fix commits referenced by the NVD entry
Identify systems that load the ltc4282 driver and prioritize them for patching
Restrict local shell access to trusted users on affected hosts until the patch is deployed

Patch Information

The fix adds the missing return statement in the VGPIO minimum alarm voltage read path. The patch is committed to upstream stable trees and referenced by hashes 00feb1c, 08aee6d, 338d655, and a0668ac. See Kernel Git Commit 338d655 and Kernel Git Commit 08aee6d for backport availability across supported stable branches.

Workarounds

Unload the ltc4282 module with modprobe -r ltc4282 on systems that do not require the driver
Blacklist the module via /etc/modprobe.d/blacklist-ltc4282.conf where hardware monitoring for the LTC4282 is not needed
Tighten permissions on /sys/class/hwmon/ entries to limit read access to privileged accounts

bash

# Configuration example: blacklist the vulnerable driver where not required
echo "blacklist ltc4282" | sudo tee /etc/modprobe.d/blacklist-ltc4282.conf
sudo modprobe -r ltc4282