CVE-2026-36603 json
Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 exposes 15 of 18 UPnP IGD actions without authentication on port 1900, incl…
published 5mo ago modified 3mo ago also EUVD-2026-34142
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 11%
- public exploits
- 0
- none known
Summary
Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 exposes 15 of 18 UPnP IGD actions without authentication on port 1900, including AddPortMapping and GetExternalIPAddress. UPnP is enabled by default through the admin interface, allowing any unauthenticated LAN device to create arbitrary port forwarding rules and access WAN traffic statistics.
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 5mo ago
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 8.1 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Classification
- Weakness
-
- CWE-306 Missing Authentication for Critical Functionality
References
Sources
- CVE List CVE-2026-36603
- NVD CVE-2026-36603
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