How severe is CVE-2021-3774?

CVE-2021-3774 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-3774 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3774?

CVE-2021-3774 affects Meross Mss550x Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3774?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-3774 published?

CVE-2021-3774 was published on 2021-11-05 and last updated on 2026-06-17.

CVE-2021-3774

CVE-2021-3774 is a high-severity vulnerability in Meross Mss550x Firmware with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-319.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 4.3
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-319
Affected product: Meross Mss550x Firmware
Published: 2021-11-05
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-3774?: 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.
How severe is CVE-2021-3774?: CVE-2021-3774 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-3774 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3774?: CVE-2021-3774 affects Meross Mss550x Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3774?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-3774 published?: CVE-2021-3774 was published on 2021-11-05 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:o:meross:mss550x_firmware:*:*:*:*:*:*:*:*

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