CVE-2026-18686Public exploitNetwork attack vector

Pre-authentication root command execution via stored password

Published Aug 4, 2026 · Updated Aug 4, 2026

Command injection in GL.iNet Beryl AX firmware 4.4.0 through 4.4.5 allows remote attackers to execute commands through the nas-web RPC wrapper. The unauthenticated add_user method stores an attacker-controlled password, and Samba user synchronization later inserts the decoded value into an smbpasswd shell command without neutralization. The chain requires available NAS storage and a Samba share containing the created user, after which the injected command runs as root.

CVSS severityUnavailable

Unscored

EPSS probability2.61%

Next 30 days · Sep 16, 2026

Known exploitationUnconfirmed

Based on sourced intelligence

Hinoki checkNot available

Coverage for this vulnerability

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Summary

What happened

The record

CVE: CVE-2026-18686
Published: Aug 4, 2026
Updated: Aug 4, 2026

Vendor: GL.iNet
Product: GL-MT3000
Classifications: CWE-74, CWE-77, T1059.004, T1190

Attack vector: network
Privileges: unauthenticated

Timeline

How it unfolded

Aug 4, 2026CVE publishedPublication date reported by the CVE source.
Aug 4, 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.

Affected versionversion=4.4.0
Affected versionversion=4.4.1
Affected versionversion=4.4.2
Affected versionversion=4.4.3
Affected versionversion=4.4.4
Affected versionversion=4.4.5

What conditions does exploitation require?

Attack vectornetwork

Required privilegesunauthenticated

What is affected?

GL.iNet · GL-MT3000version=4.4.0; version=4.4.1; version=4.4.2; version=4.4.3; version=4.4.4; version=4.4.5

Published CVSS scores

10.0VulDB CNAAV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:C

9.8VulDB CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R

9.3VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

9.8VulDB CNACVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R

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.

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

No observations available

Sep 9, 2026Sep 15, 2026

Latest reporting daySep 15, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesunauthenticated

Known exploitationUnconfirmed

Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')

T1059.004Unix Shell

T1190Exploit Public-Facing Application

Public exploit references

GL.iNet MT3000 nas-web add_user/add_share second-order pre-auth RCE PoCfunctional · demonstrated

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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