What is the CVSS score of CVE-2025-52221?

CVE-2025-52221 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of N A are affected by CVE-2025-52221?

Tenda AC6 routers running firmware 15.03.05.16_multi are vulnerable to unauthenticated remote denial-of-service attacks that can disable network connectivity for all users behind the affected device.

How to fix or mitigate CVE-2025-52221?

Within 24 hours: Identify all Tenda AC6 routers in your environment and their current firmware versions via network inventory scan. Within 7 days: Check Tenda security advisories for firmware updates; if available, test and deploy to non-production devices first. Within 30 days: Complete production deployment of patched firmware to all affected Tenda AC6 units, prioritizing business-critical network segments. If firmware updates are unavailable from Tenda, implement network-level access controls to restrict HTTP access to router management interfaces from untrusted networks.

N A CVE-2025-52221

EUVD-2025-209313 CRITICAL

Classic Buffer Overflow (CWE-120)

2026-04-08 mitre

Buffer Overflow Tenda N A

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Severity Changed

Apr 13, 2026 - 11:37 NVD

HIGH CRITICAL

CVSS changed

Apr 13, 2026 - 11:37 NVD

7.5 (HIGH) 9.8 (CRITICAL)

EUVD ID Assigned

Apr 08, 2026 - 18:16 euvd

EUVD-2025-209313

Analysis Generated

Apr 08, 2026 - 18:16 vuln.today

CVE Published

Apr 08, 2026 - 00:00 nvd

HIGH 7.5

DescriptionNVD

Tenda AC6 15.03.05.16_multi is vulnerable to Buffer Overflow in the formSetCfm function via the funcname, funcpara1, and funcpara2 parameters.

AnalysisAI

Buffer overflow in Tenda AC6 router firmware version 15.03.05.16_multi enables unauthenticated remote denial-of-service attacks via crafted HTTP requests to formSetCfm function. Attackers can trigger service disruption by sending malicious funcname, funcpara1, or funcpara2 parameters without authentication. The network-accessible attack vector with low complexity makes this exploitable from the internet. No public exploit identified at time of analysis. Low observed exploitation activity (EPSS 0.02%).

Technical ContextAI

CWE-120 buffer overflow in formSetCfm function results from inadequate input validation on three HTTP parameters. Network-reachable web interface accepts oversized parameter strings, causing stack or heap corruption that terminates service availability. CVSS vector PR:N confirms unauthenticated attack surface directly exposed to WAN/LAN requests.

RemediationAI

No vendor-released patch identified at time of analysis. Tenda has not published security advisory or firmware update addressing CVE-2025-52221 for AC6 15.03.05.16_multi. Users should monitor Tenda official support portal for firmware releases. Immediate mitigations: disable remote administration interface, restrict web management access to trusted internal IP ranges via firewall rules, place device behind network segmentation boundaries. Consider hardware replacement if vendor discontinues AC6 support. Technical analysis available at https://github.com/faqiadegege/IoTVuln/blob/main/tendaAc6_formSetCfm_funcname_overflow/detail.md and NVD advisory https://nvd.nist.gov/vuln/detail/CVE-2025-52221 for monitoring patch availability.