CVE-2026-74506

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix UAF when sending a message

In afs_make_call(), there's a race with async call reception and

destruction. If a call is dispatched that doesn't have call->write_iter

set (used to specify the data content for FS.StoreData), then the first

rxrpc_kernel_send_data() will not set MSG_MORE in the msghdr.

Once rxrpc_send_data() queues the last request packet, the response could

come in at any time and cause the call to be completed and put. However,

afs_make_call() will look at the call again to see it ->write_iter should

be handled - something it's only allowed to do if it has its own ref on the

call. Whilst this is the case for synchronous calls, it isn't true for

async calls such as FS.FetchData.

There's also a potential UAF in afs_make_call() in the event that an

asynchronous call is being sent, but the call fails in some way (e.g. it

gets aborted from the server). The problem there is that afs_make_call()

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References