NVD / CVE Program· CNA Linux

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

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 0ea70fb46940620848c08d9d399455c9e82fecdb, 48d09dea506de667eb55f939bf98eec721effbdb, 5.3.

Low priority for now. Upgrade to Linux Linux 0ea70fb46940620848c08d9d399455c9e82fecdb, 48d09dea506de667eb55f939bf98eec721effbdb, 5.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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().

Memory safety

Published: Jul 19, 2026
Updated: Oct 19, 2026
EPSS: 0.1% · 2th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 08523d5a2f4a9e4202e00d282c164d453cabe2d2, 5.3affected
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 0ea70fb46940620848c08d9d399455c9e82fecdbaffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 8be6685cdd1255bcc85f9b59e4bfc313aefc5c1baffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before c5580114e0492bcd2e0a37613ed4c311e3fa3d4daffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 7713f4aafb577ff49fa67f0488d9c7dddc64d6ceaffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 6324423a8e6591f41a16c09a8f9a84e554ac147caffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 48d09dea506de667eb55f939bf98eec721effbdbaffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before 8c3af18bb0d7c921a5219194037509463eb2ffdeaffected · git
- b9a1e627405d68d475a3c1f35e685ccfb5bbe668 and later · before aaec7096f9961eb223b5b149abe9495525c205d9affected · git
- 5.2.12 and later · before 5.3affected · semver

Affected versions · NVD (7)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel5.2.12 and later · before 5.10.259
linux linux kernel5.11 and later · before 5.15.210
linux linux kernel5.16 and later · before 6.1.176
linux linux kernel6.2 and later · before 6.6.143
linux linux kernel6.7 and later · before 6.12.93
linux linux kernel6.13 and later · before 7.0.11
linux linux kernel7.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.176-1	6.1.176-1
Debian:13	linux	before 6.12.94-1	6.12.94-1
Debian:14	linux	before 7.0.12-1	7.0.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
90Now
CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
89Now
CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2026-64118Jul 19, 2026 · qed: fix double free in qed_cxt_tables_alloc()
33Monitor
← EarlierCVE-2026-64121Jul 19, 2026 · net: ifb: report ethtool stats over num_tx_queues
28Monitor
Later →CVE-2026-64125Jul 19, 2026 · net: bcmgenet: keep RBUF EEE/PM disabled
39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	0ea70fb46940620848c08d9d399455c9e82fecdb	Vendor (CNA)
Linux Linux	48d09dea506de667eb55f939bf98eec721effbdb	Vendor (CNA)
Linux Linux	5.3	Vendor (CNA)
Linux Linux	6324423a8e6591f41a16c09a8f9a84e554ac147c	Vendor (CNA)
Linux Linux	7713f4aafb577ff49fa67f0488d9c7dddc64d6ce	Vendor (CNA)
Linux Linux	8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b	Vendor (CNA)
Linux Linux	8c3af18bb0d7c921a5219194037509463eb2ffde	Vendor (CNA)
Linux Linux	aaec7096f9961eb223b5b149abe9495525c205d9	Vendor (CNA)
Linux Linux	c5580114e0492bcd2e0a37613ed4c311e3fa3d4d	Vendor (CNA)
debian:linux	6.1.176-1 · Debian:12	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log (2)

SSVC exploitation— → noneOct 16, 2026, 5:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/0ea70fb46940620848c08d9d399455c9e82fecdb

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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