Meross MSS550X Missing Encryption of Sensitive Data

published 2021-11-05 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27043

cvss: 7.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits: 0; none known

Meross Smart Wi-Fi 2 Way Wall Switch (MSS550X), on its 3.1.3 version and before, creates an open Wi-Fi Access Point without the required security measures in its initial setup. This could allow a remote attacker to obtain the Wi-Fi SSID as well as the password configured by the user from Meross app via Http/JSON plain request.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 18 mo ago (2025-04-23)

Exploit prediction

0.73% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

Meross Meross Smart Wi-Fi 2 Way Wall Switch

Classification

Weakness

CWE-319 Cleartext Transmission of Sensitive Information

References

incibe.es /en/incibe-cert/notices/aviso/meross-mss550x-missing-encryption-sensitive-data

Sources

CVE List CVE-2021-3774
NVD CVE-2021-3774

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary