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VulnerabilityPublished Updated

CVE-2026-23428: Linux kernel · ksmbd: fix use-after-free of share_conf in compound request

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in eae0dc86f71e6f3294c0cd7ffc05039258d243af : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in eae0dc86f71e6f3294c0cd7ffc05039258d243af, d08417981155883068b7260d9500ca306a03edac, c33615f995aee80657b9fdfbc4ee7f49c2bd733d +7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.15.121 <5.15.203
  • >=6.1.36 <6.1.167
  • >=6.3.10 <6.4
Fixed in
  • eae0dc86f71e6f3294c0cd7ffc05039258d243af
  • d08417981155883068b7260d9500ca306a03edac
  • c33615f995aee80657b9fdfbc4ee7f49c2bd733d
  • c742b46a153d3ff95ff0825ab1950c87b9e14470
  • a5929c2020ce54e1dcbd1078c0f30b8aaf73c105
  • 806f13752652216db0c309392b4db3e64eeed4f2
  • 7f7468fd2a7554cea91b7d430335a3dbf01dcc09
  • 6.4
  • 6.1.167
  • 5.15.203
LinuxLinuxAffected
  • =6.4
Fixed in–

AI-suggested

The vulnerability has been fixed in Linux kernel versions 5.15.203, 6.1.167, 6.4, and later. Users and administrators should upgrade to these or newer kernel versions to remediate the issue. No additional mitigations or workarounds are indicated in the advisory.

Description

CVE-2026-23428 is a critical use-after-free vulnerability in the Linux kernel's ksmbd SMB server component. It occurs when compound SMB2 requests reuse a tree connection object without validating its state, leading to dereferencing freed memory. This flaw can cause kernel crashes or potentially allow code execution. The issue has been fixed in Linux kernel versions 5.15.203, 6.1.167, 6.4, and later.

References

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