VulnerabilityDeferred

CVE-2026-36609

Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password.

HIGH 7.3EPSS 0.17%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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: 7.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS: 0.17% probability · 6th percentile
CISA KEV: Not listed
Weakness: CWE-327, CWE-341
Source: cve@mitre.org

References

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.