CVE-2026-43379Network attack vector

Kernel memory corruption via expired RCU pointer

Published May 8, 2026 · Updated May 8, 2026

Use-after-free in the Linux Kernel ksmbd server allows remote attackers to corrupt kernel memory during lease-break close handling. smb_lazy_parent_lease_break_close() dereferences f_opinfo after leaving its RCU read-side critical section, allowing a concurrent writer to free the object first. Exposure requires reachable ksmbd service and the race to coincide with that free; published sources establish no reliable crash or code-execution result.

CVSS severity9.8
Critical
EPSS probability0.44%
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 the Linux Kernel ksmbd server allows remote attackers to corrupt kernel memory during lease-break close handling. smb_lazy_parent_lease_break_close() dereferences f_opinfo after leaving its RCU read-side critical section, allowing a concurrent writer to free the object first. Exposure requires reachable ksmbd service and the race to coincide with that free; published sources establish no reliable crash or code-execution result.

The record

CVE
CVE-2026-43379
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1190
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=27b40b7bfcd121fe13a150ffe11957630cf49246 <bf4d66d72e4a9e268c1012c331ce9eaedb5e2086
  2. Affected versionversion=5fb282ba4fef8985a5acf2b32681f2ec07732561 <960699317d39f46611f4ebeb69edc567c1f4e6b6
  3. Affected versionversion=5fb282ba4fef8985a5acf2b32681f2ec07732561 <b3568347c51c46e2cabc356bc34676df98296619
  4. Affected versionversion=5fb282ba4fef8985a5acf2b32681f2ec07732561 <dbbd328cf58261ca239756fe1c0d10c9518d3399
  5. Affected versionversion=5fb282ba4fef8985a5acf2b32681f2ec07732561 <eac3361e3d5dd8067b3258c69615888eb45e9f25
  6. Affected versionversion=6.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=27b40b7bfcd121fe13a150ffe11957630cf49246 <bf4d66d72e4a9e268c1012c331ce9eaedb5e2086; version=5fb282ba4fef8985a5acf2b32681f2ec07732561 <960699317d39f46611f4ebeb69edc567c1f4e6b6; version=5fb282ba4fef8985a5acf2b32681f2ec07732561 <b3568347c51c46e2cabc356bc34676df98296619; version=5fb282ba4fef8985a5acf2b32681f2ec07732561 <dbbd328cf58261ca239756fe1c0d10c9518d3399; version=5fb282ba4fef8985a5acf2b32681f2ec07732561 <eac3361e3d5dd8067b3258c69615888eb45e9f25; version=6.9

Published CVSS scores

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

T1190Exploit Public-Facing Application

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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