CVE-2026-99231

--- CME Mitigation Guidance (2026-11-04) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.

The highest-value action is to ensure the io_uring waitid wake-up handler claims request ownership before clearing ->head so concurrent operations cannot free the request without wait queue locking: upgrade to the fixed release, which defer clearing ->head until after the wake-up handler has acquired ownership of the request, closing all 2 injection vectors (concurrent io_uring waitid request completion, concurrent io_uring waitid request cancellation). Until patched, this is only a concern on Linux systems where local unprivileged users have permission to submit io_uring operations — non-Linux operating systems are unaffected — so Restrict and audit local unprivileged user access and permissions to submit io_uring operations. As a compensating measure, zero-initialize kernel slab allocations on creation using init_on_alloc or INIT_STACK_ALL_ZERO to reduce predictable reuse of stale request data, maintain SELinux in enforcing mode to confine local process domains and limit post-exploitation damage, map logged-in users to confined SELinux domains to restrict the privileges of unprivileged accounts, deploy an endpoint detection and response agent to identify anomalous privilege elevation and unauthorized shell generation, use Falco or eBPF runtime security to monitor kernel and process behavior for unexpected privilege escalations, and enable kernel address space layout randomization to hinder reliable code-execution payload crafting. These controls limit blast radius and contain exploitation, but they do not fix the underlying race condition use-after-free defect — apply the upstream patch to fully remediate.

Highest-impact CME: CME-1005 Runtime Memory Error Detection (KASAN/HWASan) (high)