CVE-2026-23137

What it actually does

Memory leak in Linux kernel device tree unittest code when of_resolve_phandles fails after allocation of unittest_data, leaving the buffer unfreed on error paths.

Why it matters to the business

Over extended operation of kernel test suites, gradual memory exhaustion can occur in development or CI environments, leading to reduced stability during prolonged testing; production kernels are unaffected as this resides only in unittest paths.

How an attack unfolds

An attacker with local access triggers the unittest_data_add error path by causing of_resolve_phandles to fail after allocation; repeated triggering exhausts kernel memory, resulting in availability impact. No named threat actors or ransomware campaigns are associated.

How to fix it

Update the Linux kernel to the fixed commit f09b0f705bd7197863b90256ef533a6414d1db2c or later stable releases containing the scope-based cleanup with __free(kfree) and retain_and_null_ptr usage.

How to confirm the fix worked

Confirm the presence of the fix commit in the kernel source; review unittest_data_add implementation for automatic cleanup helpers and absence of manual kfree on all error paths.

Typical attack path

1. Obtain local user access to a system running the affected kernel
2. Invoke or manipulate device tree unittest execution to reach unittest_data_add
3. Force of_resolve_phandles failure after memory allocation
4. Repeat to accumulate leaked memory until system impact

How to detect it

Search kernel logs and test execution traces for repeated calls to unittest_data_add followed by of_resolve_phandles failures without corresponding kfree; no public exploitation artifacts exist.

What your security team should do

• Prioritize upgrade of development and CI kernel images to the fixed commit within standard patch cycles
• Monitor EPSS trend for any increase indicating rising exploit interest
• Restrict local access to systems executing device tree unittests