CVE-2026-90174

Kernel memory disclosure and crash via oversized hash

Published Sep 17, 2026 · Updated Sep 18, 2026

Out-of-bounds read in Linux ksmbd 5.15 through 7.2.5 allows local users to read kernel heap data or crash the host kernel. ksmbd_alloc_user trusts the 16-bit hash_sz in a mountd IPC login response and copies as many as 65,535 bytes from an 18-byte hash buffer. Exploitation requires a running ksmbd server and a matching session-setup handle; CAP_NET_ADMIN is required only when its optional kernel check is enabled.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Oct 18, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Linux ksmbd 5.15 through 7.2.5 allows local users to read kernel heap data or crash the host kernel. ksmbd_alloc_user trusts the 16-bit hash_sz in a mountd IPC login response and copies as many as 65,535 bytes from an 18-byte hash buffer. Exploitation requires a running ksmbd server and a matching session-setup handle; CAP_NET_ADMIN is required only when its optional kernel check is enabled.

The record

CVE
CVE-2026-90174
Published
Sep 17, 2026
Updated
Sep 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.15
  2. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <497c221bf6b2f659511719a6acfae84cc1be1caf
  3. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <7405d0ba294306721843bc551611775e6edef516

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <497c221bf6b2f659511719a6acfae84cc1be1caf; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <7405d0ba294306721843bc551611775e6edef516

Published CVSS scores

7.1Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

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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