Linux Kernel up to 7.2.5 octeontx2-af rvu_mbox_init allocation of resources

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been rated as very critical. The impacted element is the function rvu_mbox_init of the component octeontx2-af. This manipulation causes allocation of resources. This vulnerability is tracked as CVE-2026-90079. The attack is restricted to local execution. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.2.5. Affected by this vulnerability is the function rvu_mbox_init of the component octeontx2-af. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-90079 since 09/11/2026. The exploitation appears to be easy. Attacking locally is a requirement. Additional levels of successful authentication are required for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch a0fcbea79f034f49bdd44915f28938922023458d/3b11a77f69980932c3924054d66e565c9a135747 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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