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Ac21 Firmware CVE-2025-65226

MEDIUM
Classic Buffer Overflow (CWE-120)
2025-11-20 cve@mitre.org
4.3
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 4.3 (MEDIUM). Attack characteristics: adjacent network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.05%.

Exploit ScenarioDerived

An attacker could exploit this vulnerability to overflow a buffer to corrupt adjacent memory. No authentication is required to exploit this vulnerability.

Monitor Track and reassess. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Tenda AC21 V16.03.08.16 is vulnerable to Buffer Overflow via the deviceId parameter in /goform/saveParentControlInfo. Rated medium severity (CVSS 4.3), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. Tenda AC21 V16.03.08.16 is vulnerable to Buffer Overflow via the deviceId parameter in /goform/saveParentControlInfo. Affected products include: Tenda Ac21 Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 4.3 MEDIUM
AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Lifecycle Timeline

2
PoC Detected
Nov 21, 2025 - 17:24 vuln.today
Public exploit code
CVE Published
Nov 20, 2025 - 15:17 nvd
MEDIUM 4.3

DescriptionCVE.org

Tenda AC21 V16.03.08.16 is vulnerable to Buffer Overflow via the deviceId parameter in /goform/saveParentControlInfo.

Executive ViewAI

Why It Matters

Organizations using Tenda AC21 V16.03.08.16 should be aware of moderate risk from CVE-2025-65226, a buffer overflow vulnerability rated CVSS 4.3. Exploitation could cause memory corruption or application crashes. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.

Threat Intelligence Overview

EPSS Score
0.0%
Top 85% exploitable
Exploit
POC
Public exploit code exists

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.0%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
Poc
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
Low

Priority Score

42
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +22
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)CVE.org

cpe:2.3:o:tenda:ac21_firmware:16.03.08.16:*:*:*:*:*:*:*
CVE-2025-9605 HIGH POC
8.9 Aug 29

A security vulnerability has been detected in Tenda AC21 and AC23 16.03.08.16. Rated high severity (CVSS 8.9), this vuln

CVE-2022-44163 HIGH POC
7.5 Nov 21

Tenda AC21 V16.03.08.15 is vulnerable to Buffer Overflow via function formSetMacFilterCfg. Rated high severity (CVSS 7.5

CVE-2022-44158 HIGH POC
7.5 Nov 21

Tenda AC21 V16.03.08.15 is vulnerable to Buffer Overflow via function via set_device_name. Rated high severity (CVSS 7.5

CVE-2022-40076 HIGH POC
7.5 Sep 19

Tenda AC21 V16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, function: fromSetWifiGusetBasic. Rated high sev

CVE-2022-40075 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, form_fast_setting_wifi_set. Rated high severit

CVE-2022-40074 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, setSchedWifi. Rated high severity (CVSS 7.5),

CVE-2022-40073 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, saveParentControlInfo. Rated high severity (CV

CVE-2022-40072 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, function: setSmartPowerManagement. Rated high

CVE-2022-40071 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, formSetDeviceName. Rated high severity (CVSS 7

CVE-2022-40070 HIGH POC
7.5 Sep 19

Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via bin/httpd, function: formSetFirewallCfg. Rated high severi

CVE-2022-40069 HIGH POC
7.5 Sep 19

]Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, function: fromSetSysTime. Rated high severity

CVE-2022-40068 HIGH POC
7.5 Sep 19

Tenda AC21 V16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, function: formSetQosBand. Rated high severity (

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