CVE-2026-64123: Linux kernel · net: hsr: defer node table free until after RCU readers
Source GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| 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
- nvd.nist.gov/vuln/detail/CVE-2026-64123 (opens in a new tab)
- git.kernel.org/stable/c/0ea70fb46940620848c08d9d399455c9e82fecdb (opens in a new tab)
- git.kernel.org/stable/c/6324423a8e6591f41a16c09a8f9a84e554ac147c (opens in a new tab)
- git.kernel.org/stable/c/7713f4aafb577ff49fa67f0488d9c7dddc64d6ce (opens in a new tab)
- git.kernel.org/stable/c/8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b (opens in a new tab)
- git.kernel.org/stable/c/8c3af18bb0d7c921a5219194037509463eb2ffde (opens in a new tab)
- git.kernel.org/stable/c/aaec7096f9961eb223b5b149abe9495525c205d9 (opens in a new tab)
- git.kernel.org/stable/c/c5580114e0492bcd2e0a37613ed4c311e3fa3d4d (opens in a new tab)