Cyber Resilience

CVE-2025-52221

Memory Safety in Tenda Ac6 Firmware 15.03.05.16_multi

Public PoCMemory Safety
Published
08 April 2026
Modified
25 July 2026
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0039 32th percentile
Risk Priority 71 floored blend · peak EPSS

Summary

CVE-2025-52221 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Tenda Ac6 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-52221 is a buffer overflow vulnerability affecting Tenda AC6 routers running firmware version 15.03.05.16_multi. The issue resides in the formSetCfm function and can be triggered through specially crafted values in the funcname, funcpara1, and funcpara2 parameters. It is associated with CWE-787 (Out-of-bounds Write) and CWE-120 (Buffer Copy without Checking Size of Input), and was published on 2026-04-08T18:24:51.257 with a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

The vulnerability enables remote exploitation over the network with low complexity, requiring no privileges, authentication, or user interaction. Attackers can send malicious requests to the affected formSetCfm endpoint, potentially leading to arbitrary code execution, data disclosure, system modification, or denial of service due to the high impact on confidentiality, integrity, and availability.

Technical details on the vulnerability, including exploit information, are documented in community GitHub repositories such as https://github.com/faqiadegege/IoTVuln/blob/main/tendaAc6_formSetCfm_funcname_overflow/detail.md and https://github.com/xiaotea/iot-vulnerability-collection/blob/main/README.md. No vendor advisories or patches are referenced in the available data.

EU & UK References

Vulnerability Data

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

CWE(s)
CWE-787CWE-120

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-60339Same product: Tenda Ac6
CVE-2025-60337Same product: Tenda Ac6
CVE-2023-40843Same product: Tenda Ac6
CVE-2023-40845Same product: Tenda Ac6
CVE-2023-40840Same product: Tenda Ac6
CVE-2023-40842Same product: Tenda Ac6
CVE-2023-40846Same product: Tenda Ac6
CVE-2023-40847Same product: Tenda Ac6
CVE-2023-40841Same product: Tenda Ac6
CVE-2023-40844Same product: Tenda Ac6

Affected Assets

tenda
ac6 firmware
15.03.05.16_multi

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.

SI-10 Information Input Validation good match

Input validation directly enforces size checks before buffer copies.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles require bounds checking and safe buffer handling in design.

SI-16 Memory Protection partial match

Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify bounds-checking and safe memory handling.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

A.8.32 Change management partial match
prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References