Cyber Resilience

CVE-2025-10838

Memory Safety in Tenda Ac21 Firmware ≤ 16.03.08.16

Public PoCMemory Safety
Published
23 September 2025
Modified
03 October 2025
Patch / advisory
View advisory
CVSS Score v4 7.4
Click a component to see what it means
Raw vectorCVSS:4.0/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
EPSS Score 0.0095 58th percentile
Risk Priority 38 floored blend · peak EPSS

Summary

CVE-2025-10838 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Tenda Ac21 Firmware. Its CVSS base score is 7.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 42% of CVEs by exploit likelihood; 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-2025-10838 is a buffer overflow vulnerability (CWE-119, CWE-120) affecting Tenda AC21 router firmware version 16.03.08.16. The flaw exists in the sub_45BB10 function within the /goform/WifiExtraSet CGI script, where manipulation of the wpapsk_crypto argument triggers the overflow. Published on 2025-09-23, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), marking it as high severity.

Remote attackers with low privileges, such as authenticated users, can exploit this vulnerability over the network with low complexity and no user interaction. Successful exploitation enables high-impact consequences, including unauthorized access to sensitive data (C:H), modification of system integrity (I:H), and denial of service or code execution (A:H), potentially resulting in full router compromise. A proof-of-concept exploit is publicly available.

Advisories referenced on VulDB (ctiid.325200, id.325200, submit.657126) and a GitHub repository detail the vulnerability, including a POC demonstrating the buffer overflow. No specific patches or mitigation steps are outlined in the provided disclosures.

EU & UK References

Vulnerability Data

A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function sub_45BB10 of the file /goform/WifiExtraSet. The manipulation of the argument wpapsk_crypto leads to buffer overflow. It is possible to initiate the attack remotely. The exploit is…

more

publicly available and might be used.

CWE(s)
CWE-119CWE-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 →
T1055 Process Injection Stealth
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges.
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-2025-12611Same product: Tenda Ac21
CVE-2026-4565Same product: Tenda Ac21
CVE-2025-11091Same product: Tenda Ac21
CVE-2025-13446Same product: Tenda Ac21
CVE-2025-13445Same product: Tenda Ac21
CVE-2026-1637Same product: Tenda Ac21
CVE-2025-65226Same product: Tenda Ac21
CVE-2025-9605Same product: Tenda Ac21
CVE-2025-5854Same vendor: Tenda
CVE-2026-7031Same vendor: Tenda

Affected Assets

tenda
ac21 firmware
≤ 16.03.08.16

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)
  • V17.3.2
  • V5.2.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and analysis can find missing size checks before deployment.

SI-10 Information Input Validation good match

Input validation directly enforces size checks before buffer copies.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require memory-safe design and coding that structurally avoids buffer-boundary violations.

SI-16 Memory Protection partial match

Memory protection restricts exploitation impact of buffer overflows without eliminating the underlying coding flaw.

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 SDLC practices (bounds checking, safe APIs, reviews) directly prevent this class of flaw.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

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 catches out-of-bounds accesses before release, covering most instances of the weakness.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

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

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

References