CVE-2026-90079 octeontx2-af: fix cn20k mailbox lifetime on repeated rvu_mbox_init()
A use-after-free vulnerability in the Linux kernel octeontx2-af driver allows local attackers to cause denial of service or execute code via improper mailbox initialization handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90079?
CVE-2026-90079 is an use after free vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-af: fix cn20k mailbox lifetime on repeated rvu_mbox_init()
rvu_mbox_init() is called separately for AF-PF mailboxes during probe and for AF-VF mailboxes when SR-IOV is enabled. Each call used to allocate a new ng_rvu object, leaking the first allocation when the pointer was overwritten on the second call.
Sharing one ng_rvu across both paths exposed several teardown bugs: the error path freed all cn20k mailbox DMA and kfree()d ng_rvu even when only the failing init type should be unwound, leaving live AF-PF mailbox memory in use after an AF-VF init failure. mutex_init() was also re-run on the AF-VF path while AF-PF mailbox handlers could still hold rvu->mbox_lock. Probe and SR-IOV failure paths did not release cn20k mailbox DMA either, since cleanup only happened in rvu_remove().
Allocate ng_rvu once with devm_kzalloc(), initialize mbox_lock in the same block, unwind only the mailbox memory for the failing init type, and free cn20k mailbox DMA from the probe and pci_enable_sriov() error paths.
Which versions are affected by CVE-2026-90079?
How do I fix CVE-2026-90079?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-90079 being exploited?
There is no known exploitation of CVE-2026-90079 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90079, DEBIAN-CVE-2026-90079, GHSA-g2m5-qf5x-2p4w, UBUNTU-CVE-2026-90079.