CVE-2026-66154

Unauthorized changes via insufficient certificate validation

Published Aug 11, 2026 · Updated Aug 11, 2026

Improper certificate validation in SonicWall GMS 9.5.1 and earlier allows man-in-the-middle attackers to make unauthorized changes. The privileged communication workflow insufficiently validates a certificate before trusting the connection; SonicWall has not disclosed the component or exact validation error. Exploitation requires controlled adjacent-network conditions and successful interception, and the disclosed consequence is limited to unauthorized changes.

CVSS severity8.3
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in SonicWall GMS 9.5.1 and earlier allows man-in-the-middle attackers to make unauthorized changes. The privileged communication workflow insufficiently validates a certificate before trusting the connection; SonicWall has not disclosed the component or exact validation error. Exploitation requires controlled adjacent-network conditions and successful interception, and the disclosed consequence is limited to unauthorized changes.

The record

CVE
CVE-2026-66154
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
SonicWall
Product
Global Management System (GMS)
Classifications
CWE-295, T1565.002
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 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=9.5.1 and earlier versions

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

SonicWall · Global Management System (GMS)version=9.5.1 and earlier versions

Published CVSS scores

8.3CISA-ADPCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1565.002Transmitted Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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