Which versions of Ac21 Firmware are affected by CVE-2025-11091?

Organizations using Tenda AC21 face moderate risk from CVE-2025-11091, a buffer overflow vulnerability rated CVSS 7.4.

Is there a public PoC exploit available for CVE-2025-11091?

Yes, a public proof-of-concept exploit is available for CVE-2025-11091. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate CVE-2025-11091?

Within 30 days: Identify all affected systems running Tenda AC21 and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Ac21 Firmware CVE-2025-11091

Q: What is the CVSS score of CVE-2025-11091?

CVE-2025-11091 has a CVSS 4.0 base score of 7.4 (High). CVSS vector: CVSS: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 exploitation probability: 0.3%.

HIGH

Buffer Overflow (CWE-119)

2025-09-28 cna@vuldb.com

Buffer Overflow Tenda Ac21 Firmware

7.4

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

7.4 HIGH

CVSS: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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:14 vuln.today

PoC Detected

Oct 03, 2025 - 14:45 vuln.today

Public exploit code

CVE Published

Sep 28, 2025 - 02:15 nvd

HIGH 7.4

DescriptionCVE.org

A security flaw has been discovered in Tenda AC21 up to 16.03.08.16. Affected by this vulnerability is the function sscanf of the file /goform/SetStaticRouteCfg. The manipulation of the argument list results in buffer overflow. The attack can be launched remotely. The exploit has been released to the public and may be exploited.

AnalysisAI

A security flaw has been discovered in Tenda AC21 up to 16.03.08.16. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. A security flaw has been discovered in Tenda AC21 up to 16.03.08.16. Affected by this vulnerability is the function sscanf of the file /goform/SetStaticRouteCfg. The manipulation of the argument list results in buffer overflow. The attack can be launched remotely. The exploit has been released to the public and may be exploited. Affected products include: Tenda Ac21 Firmware. Version information: up to 16.03.08.16..

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.