CVE-2026-64123: In the Linux kernel, the following vulnerability has been resolved: net: hsr: defer node table free until after RCU readers HSR node-list and node-s...

Description

In the Linux kernel, the following vulnerability has been resolved: net: hsr: defer node table free until after RCU readers HSR node-list and node-status generic-netlink operations run under rcu_read_lock(). They walk hsr->node_db through hsr_get_next_node() and hsr_get_node_data(), but RTM_DELLINK teardown removes the same node table with plain list_del() and frees each node immediately. That lets a generic-netlink reader hold a struct hsr_node pointer across hsr_dellink(). In a KASAN build, widening the reader window after hsr_get_next_node() obtains the node reproduces a slab-use-after-free when the reader copies node->macaddress_A; the freeing stack is hsr_del_nodes() from hsr_dellink(). Use list_del_rcu() and defer the free through the existing hsr_free_node_rcu() callback. This matches the lifetime rule used by the HSR prune paths, which already delete nodes with list_del_rcu() and call_rcu().

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.13%

2.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < 0ea70fb46940620848c08d9d399455c9e82fecdb; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < 8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < c5580114e0492bcd2e0a37613ed4c311e3fa3d4d; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < 7713f4aafb577ff49fa67f0488d9c7dddc64d6ce; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < 6324423a8e6591f41a16c09a8f9a84e554ac147c; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < 8c3af18bb0d7c921a5219194037509463eb2ffde; >= b9a1e627405d68d475a3c1f35e685ccfb5bbe668, < aaec7096f9961eb223b5b149abe9495525c205d9; 08523d5a2f4a9e4202e00d282c164d453cabe2d2; >= 5.2.12, < 5.3
Linux	Linux	5.3

References

Timeline

Published: Jul 19, 2026
Last Modified: Jul 30, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64123?

In the Linux kernel, the following vulnerability has been resolved: net: hsr: defer node table free until after RCU readers HSR node-list and node-status generic-netlink operations run under rcu_read_lock(). They walk hsr->node_db through hsr_get_next_node() and hsr_get_node_data(), but RTM_DELLINK teardown removes the same node table with plain list_del() and frees each node immediately. That lets a generic-netlink reader hold a struct hsr_node pointer across hsr_dellink(). In a KASAN build, widening the reader window after hsr_get_next_node() obtains the node reproduces a slab-use-after-free when the reader copies node->macaddress_A; the freeing stack is hsr_del_nodes() from hsr_dellink(). Use list_del_rcu() and defer the free through the existing hsr_free_node_rcu() callback. This matches the lifetime rule used by the HSR prune paths, which already delete nodes with list_del_rcu() and call_rcu().

How severe is CVE-2026-64123?

CVE-2026-64123 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.

How do I fix CVE-2026-64123?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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