CVE-2026-36609

Published Jun 3, 2026 CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed
Description
Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 uses a static authentication nonce that does not change between requests from the same source IP. Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Mercusys
Mercusys ac12g
Vendors & Products Mercusys
Mercusys ac12g
Type Values Removed Values Added
Title Static Nonce and Predictable XOR Encoding Enable Recovery of Plaintext Passwords on Mercusys AC12G Router
Weaknesses CWE-326
Type Values Removed Values Added
Weaknesses CWE-327
CWE-341
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Static Nonce and Predictable XOR Encoding Enable Recovery of Plaintext Passwords on Mercusys AC12G Router
Weaknesses CWE-326
Type Values Removed Values Added
Description Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 uses a static authentication nonce that does not change between requests from the same source IP. Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Jun 3, 2026, 7:38 PM
Reserved
Apr 6, 2026, 12:00 AM
Status
Deferred
Published
Jun 3, 2026, 6:16 PM
Modified
Jul 22, 2026, 7:10 PM