CVE-2024-26839

What it actually does

Failure of dma_alloc_coherent in init_credit_return leaves previously allocated dd->cr_base and dd->cr_base[i] structures unfreed, producing a persistent memory leak in the hfi1 driver.

Why it matters to the business

Gradual memory exhaustion on systems using the affected kernel driver can degrade performance or trigger outages; with over 900 days since disclosure, low EPSS, and no KEV listing the issue remains low urgency but still requires patching to avoid long-term resource waste.

How an attack unfolds

An attacker with local access or the ability to induce repeated dma allocation failures (for example through concurrent workloads or hardware stress) can trigger the missing cleanup path, steadily consuming kernel memory until the system becomes unstable.

How to fix it

Update the Linux kernel to a version containing the fix for CVE-2024-26839; for the listed vim packages on Alpine v3.17 upgrade to 8.2.5055-r0 or later.

How to confirm the fix worked

Confirm the running kernel contains the commit that adds the missing deallocation of cr_base on dma_alloc_coherent failure; verify package versions match the fixed releases and monitor for absence of the leak under allocation-stress tests.

Typical attack path

1. Gain local execution or workload control on a system with the hfi1 driver loaded
2. Force repeated failure of dma_alloc_coherent calls targeting cr_base allocations
3. Allow the leak to accumulate until memory pressure causes denial of service

How to detect it

Review kernel logs for repeated dma_alloc_coherent failures around hfi1 initialization; inspect for steadily rising slab or kernel memory usage without corresponding workload growth; search process and driver load histories for hfi1 activity.

What your security team should do

• Prioritize kernel updates on any hosts exposing the hfi1 driver
• Audit systems for the vulnerable init_credit_return code path
• Apply the listed vim package updates where present even if unrelated to the kernel issue
• Monitor memory usage trends on affected hardware