How severe is CVE-2025-3666?

CVE-2025-3666 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2025-3666 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-3666?

CVE-2025-3666 affects Totolink A3700r Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-3666?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-3666 have an EU (EUVD) identifier?

Yes. CVE-2025-3666 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11153.

When was CVE-2025-3666 published?

CVE-2025-3666 was published on 2025-04-16 and last updated on 2026-06-17.

CVE-2025-3666

CVE-2025-3666 is a medium-severity vulnerability in Totolink A3700r Firmware with a CVSS 3.x base score of 5.3. 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-266.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
CVSS v4: 6.9
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-11153
Weakness: CWE-266
Affected product: Totolink A3700r Firmware
Published: 2025-04-16
Last modified: 2026-06-17

Description

A vulnerability was found in TOTOLINK A3700R 9.1.2u.5822_B20200513 and classified as critical. Affected by this issue is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. The manipulation leads to improper access controls. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2025-3666?: A vulnerability was found in TOTOLINK A3700R 9.1.2u.5822_B20200513 and classified as critical. Affected by this issue is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. The manipulation leads to improper access controls. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2025-3666?: CVE-2025-3666 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2025-3666 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-3666?: CVE-2025-3666 affects Totolink A3700r Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-3666?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-3666 have an EU (EUVD) identifier?: Yes. CVE-2025-3666 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11153.
When was CVE-2025-3666 published?: CVE-2025-3666 was published on 2025-04-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:totolink:a3700r_firmware:9.1.2u.5822_b20200513:*:*:*:*:*:*:*

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