CVE-2026-80877

What it actually does

Memory leak of a newly allocated vllist structure in afs_update_cell() when nr_servers == 0 and the prior list is also empty, preventing displacement of the old list and causing the new allocation to be lost.

Why it matters to the business

Gradual kernel memory exhaustion on systems using the AFS filesystem, potentially leading to performance degradation, OOM kills, or system instability over extended operation periods.

How an attack unfolds

An attacker or workload triggers repeated afs_update_cell() calls that produce empty server lists, causing incremental vllist allocations that are never freed; no remote code execution or privilege escalation path exists from the leak itself.

How to fix it

Apply the upstream kernel patch resolving the vllist leak in afs_update_cell(); rebuild and deploy the fixed kernel to all affected systems.

How to confirm the fix worked

Confirm presence of the fix commit in the running kernel source or binary; monitor kernel memory statistics under AFS cell update workloads before and after the update to verify leak cessation.

Typical attack path

1. Mount or interact with an AFS cell that returns zero servers during update
2. Invoke afs_update_cell() repeatedly under the empty-list condition
3. Observe cumulative kernel memory growth without corresponding vllist release
4. Trigger OOM or performance collapse after prolonged accumulation

How to detect it

Monitor kernel slab or kmalloc memory counters associated with AFS structures for unexplained growth; review dmesg and /proc/meminfo over time during cell updates.

What your security team should do

• Identify all Linux systems running AFS and schedule kernel updates within the next maintenance window
• Add kernel memory usage alerts for AFS-related workloads
• Review AFS cell configurations to minimize empty server list scenarios where possible