What is the CVSS score of CVE-2026-2871?

CVE-2026-2871 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of DNS are affected by CVE-2026-2871?

A high-severity vulnerability in Tenda A21 wireless routers (CVE-2026-2871) allows unauthenticated attackers to compromise network devices through the IP-MAC binding function.

Is there a public PoC exploit available for CVE-2026-2871?

Yes, a public proof-of-concept exploit is available for CVE-2026-2871. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-2871?

Within 24 hours: Inventory all Tenda A21 1.0.0.0 devices in production and isolate affected units from critical networks if possible; enable all available logging and monitoring. Within 7 days: Implement network segmentation to restrict administrative access to these devices and deploy WAF rules blocking /goform/SetIpMacBind requests from untrusted sources. Within 30 days: Replace affected Tenda A21 devices with patched alternatives or equipment from vendors with active security support; document all instances and maintain audit trail of affected networks.

DNS CVE-2026-2871

HIGH

Buffer Overflow (CWE-119)

2026-02-21 cna@vuldb.com

DNS Buffer Overflow Stack Overflow A21 Firmware

8.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:04 vuln.today

PoC Detected

Feb 23, 2026 - 20:59 vuln.today

Public exploit code

CVE Published

Feb 21, 2026 - 16:16 nvd

HIGH 8.8

DescriptionCVE.org

A weakness has been identified in Tenda A21 1.0.0.0. This affects the function fromSetIpMacBind of the file /goform/SetIpMacBind. This manipulation of the argument list causes stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks.

AnalysisAI

Remote code execution in Tenda A21 1.0.0.0 firmware results from a stack buffer overflow in the SetIpMacBind function accessible via the /goform/SetIpMacBind endpoint, allowing unauthenticated remote attackers to execute arbitrary code with high integrity and availability impact. Public exploit code exists for this vulnerability, and no patch is currently available, creating significant risk for affected devices.

Technical ContextAI

Classified as CWE-119 (Buffer Overflow). Affects A21 Firmware. A weakness has been identified in Tenda A21 1.0.0.0. This affects the function fromSetIpMacBind of the file /goform/SetIpMacBind. This manipulation of the argument list causes stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks.

RemediationAI

Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible. Restrict network access to the affected service where possible.