Is CVE-2021-27707 actively exploited?

No active exploitation of CVE-2021-27707 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-27707 be exploited remotely?

Yes. CVE-2021-27707 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-27707?

CVE-2021-27707 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-27707

CWE-120Published: April 14, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

Buffer Overflow in Tenda G1 and G3 routers with firmware v15.11.0.17(9502)_CN allows remote attackers to execute arbitrary code via a crafted action/"portMappingIndex "request. This occurs because the "formDelPortMapping" function directly passes the parameter "portMappingIndex" to strcpy without limit.

NVD Source

Technical Analysis

CVE-2021-27707 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.