← Vulnerability feed

Vulnerability record · CVE-2026-36609 · published 3 June 2026

CVE-2026-36609: Broken cryptographic algorithm vulnerability

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.

7.3 CVSS 3.1 High EPSS 0.23% · top 87.5% CWE-327 · Broken cryptographic algorithmCWE-341 · CWE-341 Deferred
7.3CVSS 3.1 base score
0.23%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
1References
22 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References

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

Track CVE-2026-36609 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Source: NIST National Vulnerability Database (record CVE-2026-36609), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.