CVE-2026-36609 | BDVDB-2026-337461 Detail

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.

Impact#

Per CVSS v3.1: confidentiality impact low, integrity impact low, availability impact low. Attack vector: network.

Weaknesses#

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

References#

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

Exploit#

No public exploit known

History#

Version 12026-06-03Record published in the CVE List.

Published

Published: 2026-06-03
Last modified: 2026-06-03

Vendor information

Vendor: Not stated
Product: Not stated

Score

7.3 High

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 5.8.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

No version data in the source record.

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.3 High

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity	Low
Availability	Low

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).