Bug 2540490 (CVE-2026-97419)

Summary: CVE-2026-97419 kernel: hsr: broadcast netlink notifications in the device's net namespace
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-24 17:00:16 UTC 
In the Linux kernel, the following vulnerability has been resolved:

hsr: broadcast netlink notifications in the device's net namespace

The HSR generic netlink family sets .netnsok = true. HSR devices can
live in network namespaces other than init_net.

Two async notifiers broadcast events with genlmsg_multicast(). They
are hsr_nl_ringerror() and hsr_nl_nodedown(). That helper delivers
only on the default genl socket in init_net. So the events always land
in init_net. The network namespace of the device does not matter.

This has two effects. A listener in the device's own namespace never
sees its own ring error and node down events. A privileged listener in
init_net receives events from HSR devices in other namespaces. The
payload carries the peer node MAC (HSR_A_NODE_ADDR) and the slave port
ifindex (HSR_A_IFINDEX).

Switch both callers to genlmsg_multicast_netns(). Other families with
.netnsok = true already do this. Examples are gtp, ovpn, team,
batman-adv, netdev-genl, ethtool and handshake.

hsr_nl_ringerror() already has the slave port. It uses
dev_net(port->dev). hsr_nl_nodedown() takes the namespace from the
master port via hsr_port_get_hsr().
Comment 1 Mauro Matteo Cascella 2026-09-29 10:52:26 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97419.mbox