CVE-2026-97613

A flaw was found in the Linux kernel's Microsoft Azure Network Adapter (MANA) driver. Under heavy network traffic, incoming packet processing can completely fill the receive completion queue, leaving no reserved space for hardware fence synchronization events. This issue causes the completion notification to be dropped and forces the driver to hang while holding the core network configuration lock until a timeout expires, resulting in a denial of service (DoS).

A denial-of-service flaw was found in the Linux kernel's Microsoft Azure Network Adapter (MANA) driver, shipped in Red Hat Enterprise Linux, Red Hat In-Vehicle OS, and the RHEL CoreOS layers of OpenShift Container Platform. The receive (RX) completion queue was sized to hold exactly one completion queue entry (CQE) per posted receive work queue entry, with no reserved slot for the additional CQE_RX_OBJECT_FENCE entry that hardware posts after the packet CQEs when MANA_FENCE_RQ is used. Under heavy network traffic, the completion queue can fill entirely with packet CQEs, leaving no slot for the fence completion, which is then dropped. The driver then waits for the fence completion while holding the RTNL network lock until a timeout expires, stalling network control-plane operations and causing a denial of service on systems using MANA network adapters. Red Hat rates the impact of this flaw as Low: triggering it requires a rare timing condition in which the RX completion queue is fully saturated at the exact moment a fence request is issued during privileged local network reconfiguration (CAP_NET_ADMIN), and the consequence is a temporary stall rather than memory corruption, information disclosure, or privilege escalation; the assigned CVSS:3.1 base score of 5.5 (Moderate) reflects the worst-case availability impact. Red Hat Enterprise Linux 6 and 7 are not affected because the MANA RX fencing code is not present in those releases. For affected streams the fix is deferred: given the Low impact and the specific conditions required to trigger the flaw, the fix is planned to be delivered in a future scheduled kernel update rather than an immediate update; the residual risk is limited to a temporary denial of service on MANA-equipped systems under heavy receive traffic.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.