CVE-2026-36609

State: Published
Severity: 7.3 High
Published: Jun 3, 2026
Updated: Jun 3, 2026
Reserved: Apr 6, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.3 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	CISA-ADP

Weaknesses

CWE-341 Predictable from Observable State
CWE-327 Use of a Broken or Risky Cryptographic Algorithm

Affected Products

Product	Versions
n/an/a	n/aAffected

References

https://github.com/Tymbark7372/MERCUSYS-AC12G/blob/master/advisories/CVE-2026-36609.md

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