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VulnerabilityPublished

CVE-2026-64123: Linux kernel · net: hsr: defer node table free until after RCU readers

Source GCVE Database

0
Authoritative record:CVE-2026-64123· High 7.8

Not known to be exploited · CVSS 7.8 High · fixed in c5580114e0492bcd2e0a37613ed4c311e3fa3d4d : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in c5580114e0492bcd2e0a37613ed4c311e3fa3d4d, aaec7096f9961eb223b5b149abe9495525c205d9, 6324423a8e6591f41a16c09a8f9a84e554ac147c +6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.2.12 <5.3
Fixed in
  • c5580114e0492bcd2e0a37613ed4c311e3fa3d4d
  • aaec7096f9961eb223b5b149abe9495525c205d9
  • 6324423a8e6591f41a16c09a8f9a84e554ac147c
  • 7713f4aafb577ff49fa67f0488d9c7dddc64d6ce
  • 48d09dea506de667eb55f939bf98eec721effbdb
  • 8c3af18bb0d7c921a5219194037509463eb2ffde
  • 8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b
  • 5.3
  • 0ea70fb46940620848c08d9d399455c9e82fecdb
LinuxLinuxAffected
  • =5.3
Fixed in–

AI-suggested

A fix has been implemented that changes the node removal process to use list_del_rcu() and defers freeing nodes until after RCU readers complete via the hsr_free_node_rcu() callback. Users should update to Linux kernel versions that include this fix once available.

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().

References

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