CVE-2026-97419

A flaw was found in the Linux kernel's High-availability Seamless Redundancy (HSR) subsystem. When ring error or node down events occur, asynchronous netlink notifications are broadcast exclusively to the root network namespace rather than the device's specific network namespace. This issue allows a local user in the initial network namespace to intercept sensitive network metadata, including peer Media Access Control (MAC) addresses and interface indices from isolated environments, resulting in cross-namespace information disclosure. Additionally, listeners within the device's designated namespace fail to receive these status notifications.

A moderate severity flaw was found in the Linux kernel High-availability Seamless Redundancy (HSR) subsystem. The HSR generic netlink family permits HSR devices to exist in network namespaces other than the initial namespace, but the asynchronous ring error (hsr_nl_ringerror) and node down (hsr_nl_nodedown) notifiers broadcast their notifications only to the initial (root) network namespace via genlmsg_multicast(), regardless of the device's own namespace. As a result, a local user able to listen in the initial network namespace could observe ring error and node down notifications for HSR devices in other namespaces, exposing limited network metadata such as peer node MAC addresses (HSR_A_NODE_ADDR) and slave port interface indices (HSR_A_IFINDEX), while listeners in the device's own namespace never received these status events. Red Hat Enterprise Linux 9 and 10, Red Hat In-Vehicle OS 2, and OpenShift Container Platform releases based on RHEL CoreOS 9 are affected; the fix is currently deferred for these products, and the residual risk is limited to local cross-namespace disclosure of network metadata and to missing HSR status notifications within the device's namespace. Red Hat Enterprise Linux 6, 7, and 8 are not affected because the vulnerable code is not present in those releases.

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.