CVE-2026-43378Network attack vector

Unauthenticated kernel compromise via stale opinfo dereference

Published May 8, 2026 · Updated May 8, 2026

Use-after-free in Linux Kernel ksmbd allows remote attackers to corrupt kernel memory through an SMB2 CREATE request without authentication. In smb2_open(), code dereferences fp->f_opinfo after leaving its RCU read-side critical section, allowing the referenced object to be freed concurrently. The path is reachable only when ksmbd is enabled and accepting SMB traffic; successful exploitation compromises the host kernel or interrupts the system.

CVSS severity9.8
Critical
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel ksmbd allows remote attackers to corrupt kernel memory through an SMB2 CREATE request without authentication. In smb2_open(), code dereferences fp->f_opinfo after leaving its RCU read-side critical section, allowing the referenced object to be freed concurrently. The path is reachable only when ksmbd is enabled and accepting SMB traffic; successful exploitation compromises the host kernel or interrupts the system.

The record

CVE
CVE-2026-43378
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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 <190e5f808e8058640b408ccfed25440b441a718a
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1e689a56173827669a35da7cb2a3c78ed5c53680
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <54b48ae83de8bb06e65079d96368efe359d4909c
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8f5b1a7cb009a93c48e9e334a2f59a660f9afc07
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b720c84087cb547f23ce03eab93568c1769e4556
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e1b21e6066615e7d3d3a7aa2677e415e563fd7cc

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <190e5f808e8058640b408ccfed25440b441a718a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1e689a56173827669a35da7cb2a3c78ed5c53680; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <54b48ae83de8bb06e65079d96368efe359d4909c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8f5b1a7cb009a93c48e9e334a2f59a660f9afc07; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b720c84087cb547f23ce03eab93568c1769e4556; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e1b21e6066615e7d3d3a7aa2677e415e563fd7cc

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

CWE-416Use After Free
T1210Exploitation of Remote Services

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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