CVE-2026-43239Network attack vector

Kernel memory corruption via interface-query refresh race

Published May 6, 2026 · Updated May 6, 2026

Race condition in the Linux kernel SMB client allows remote attackers to corrupt kernel interface-list state through SMB responses. SMB3_request_interfaces checks iface_last_update without iface_lock, allowing concurrent work items to update the same cifs_server_iface list and refcounts. Exploitation requires connection to a malicious or compromised SMB server; the corruption can expose kernel memory, enable code execution, or cause an oops, panic, or hang.

CVSS severity8.8
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux kernel SMB client allows remote attackers to corrupt kernel interface-list state through SMB responses. SMB3_request_interfaces checks iface_last_update without iface_lock, allowing concurrent work items to update the same cifs_server_iface list and refcounts. Exploitation requires connection to a malicious or compromised SMB server; the corruption can expose kernel memory, enable code execution, or cause an oops, panic, or hang.

The record

CVE
CVE-2026-43239
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6287eefaf21ec805d42f941bd368018cf397a7f5
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <76cc4faba0343c6db945b8dc75425b33d633e1b8
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <93e8e3ee165ae4609a1222b516b573837103d2c3
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab6564f416a6eaf1199200b6100952407b438f7d
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c3c06e42e1527716c54f3ad2ced6a034b5f3a489

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6287eefaf21ec805d42f941bd368018cf397a7f5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <76cc4faba0343c6db945b8dc75425b33d633e1b8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <93e8e3ee165ae4609a1222b516b573837103d2c3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ab6564f416a6eaf1199200b6100952407b438f7d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c3c06e42e1527716c54f3ad2ced6a034b5f3a489

Published CVSS scores

6.5Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:H
8.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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