CVE-2026-36618

Resolver metadata disclosure via CHAOS TXT queries

Published Jun 3, 2026 · Updated Jun 3, 2026

Information disclosure in Mercusys AC12G (EU) V1 firmware 200909 and 210128 allows remote attackers to read resolver metadata. The default Unbound DNS service answers version.bind and hostname.bind CHAOS TXT queries with version 1.22.0 and the internal hostname mms-unbound. Any unauthenticated LAN client able to query the router can obtain these identifiers for targeted reconnaissance.

CVSS severity4.3
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Mercusys AC12G (EU) V1 firmware 200909 and 210128 allows remote attackers to read resolver metadata. The default Unbound DNS service answers version.bind and hostname.bind CHAOS TXT queries with version 1.22.0 and the internal hostname mms-unbound. Any unauthenticated LAN client able to query the router can obtain these identifiers for targeted reconnaissance.

The record

CVE
CVE-2026-36618
Published
Jun 3, 2026
Updated
Jun 3, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-200, T1046
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1046Network Service Discovery

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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