1. Home
  2. Vulnerabilities
  3. CVE-2026-4565
9.0
HIGH CVSS 2.0
CVE-2026-4565
Tenda AC21 SetNetControlList formSetQosBand buffer overflow
Overview
Description

A vulnerability was detected in Tenda AC21 16.03.08.16. Impacted is the function formSetQosBand of the file /goform/SetNetControlList. Performing a manipulation of the argument list results in buffer overflow. The attack can be initiated remotely. The exploit is now public and may be used.

Details
INFO

Published Date :

March 23, 2026, 1:16 a.m.

Last Modified :

April 3, 2026, 11:31 a.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-4565 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Tenda ac21_firmware
2 Tenda ac21
: Total Affected Vendor : 1 | Products : 2
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 HIGH [email protected]
CVSS 3.1 HIGH [email protected]
CVSS 4.0 HIGH [email protected]
Solution
Update Tenda AC21 firmware to patch buffer overflow vulnerability.
  • Update firmware on Tenda AC21 devices.
  • Apply vendor patches when available.
  • Monitor for exploit activity.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-4565.

URL Resource
https://github.com/hellonestor/killallbug/issues/14 Exploit Issue Tracking
https://github.com/hellonestor/killallbug/releases/tag/poc Exploit
https://vuldb.com/?ctiid.352402 Permissions Required VDB Entry
https://vuldb.com/?id.352402 Third Party Advisory VDB Entry
https://vuldb.com/?submit.775119 Third Party Advisory VDB Entry
https://www.tenda.com.cn/ Product
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-4565 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-4565 weaknesses.

CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-100: Overflow Buffers Overflow Buffers CAPEC-123: Buffer Manipulation Buffer Manipulation CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-92: Forced Integer Overflow Forced Integer Overflow CAPEC-100: Overflow Buffers Overflow Buffers

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-4565 vulnerability anywhere in the article.

  • Daily CyberSecurity
The Weekly Breach: 7 Maximum CVSS Flaws and the DarkSword Exploit Unveiled

The past seven days have been an exceptionally busy period for cybersecurity defenders. Between March 16 and March 23, a staggering 1,348 new vulnerabilities were identified and logged. While the shee ... Read more

Published Date: Mar 23, 2026 (3 weeks, 4 days ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-4565 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Apr. 03, 2026

    Action Type Old Value New Value
    Added CPE Configuration AND OR *cpe:2.3:o:tenda:ac21_firmware:16.03.08.16:*:*:*:*:*:*:* OR cpe:2.3:h:tenda:ac21:1.0:*:*:*:*:*:*:*
    Added Reference Type VulDB: https://github.com/hellonestor/killallbug/issues/14 Types: Exploit, Issue Tracking
    Added Reference Type VulDB: https://github.com/hellonestor/killallbug/releases/tag/poc Types: Exploit
    Added Reference Type VulDB: https://vuldb.com/?ctiid.352402 Types: Permissions Required, VDB Entry
    Added Reference Type VulDB: https://vuldb.com/?id.352402 Types: Third Party Advisory, VDB Entry
    Added Reference Type VulDB: https://vuldb.com/?submit.775119 Types: Third Party Advisory, VDB Entry
    Added Reference Type VulDB: https://www.tenda.com.cn/ Types: Product
  • New CVE Received by [email protected]

    Mar. 23, 2026

    Action Type Old Value New Value
    Added Description A vulnerability was detected in Tenda AC21 16.03.08.16. Impacted is the function formSetQosBand of the file /goform/SetNetControlList. Performing a manipulation of the argument list results in buffer overflow. The attack can be initiated remotely. The exploit is now public and may be used.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    Added CVSS V2 (AV:N/AC:L/Au:S/C:C/I:C/A:C)
    Added CWE CWE-119
    Added CWE CWE-120
    Added Reference https://github.com/hellonestor/killallbug/issues/14
    Added Reference https://github.com/hellonestor/killallbug/releases/tag/poc
    Added Reference https://vuldb.com/?ctiid.352402
    Added Reference https://vuldb.com/?id.352402
    Added Reference https://vuldb.com/?submit.775119
    Added Reference https://www.tenda.com.cn/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 7.4
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
VS Confidentiality
VS Integrity
VS Availability
SS Confidentiality
SS Integrity
SS Availability
Base CVSS Score: 8.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 9.0
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact