What is the CVSS score of CVE-2026-2909?

CVE-2026-2909 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of Hg9 Firmware are affected by CVE-2026-2909?

A high-severity vulnerability (CVSS 8.8) affects Tenda HG9 routers, potentially allowing remote attackers to compromise network infrastructure without authentication.

Is there a public PoC exploit available for CVE-2026-2909?

Yes, a public proof-of-concept exploit is available for CVE-2026-2909. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-2909?

Within 24 hours: Identify and inventory all Tenda HG9 devices (model 300001138) in production environments and isolate them from critical network segments if possible. Within 7 days: Implement compensating controls including network access restrictions and WAF rules to block malicious ping diagnostic requests; consider disabling the ping diagnostic feature if operationally feasible. Within 30 days: Develop an exit strategy including device replacement timeline, as no patch is available and vendor support status should be verified immediately.

Hg9 Firmware CVE-2026-2909

HIGH

Buffer Overflow (CWE-119)

2026-02-22 cna@vuldb.com

Buffer Overflow Stack Overflow Hg9 Firmware

8.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:04 vuln.today

PoC Detected

Feb 23, 2026 - 20:21 vuln.today

Public exploit code

CVE Published

Feb 22, 2026 - 02:16 nvd

HIGH 8.8

DescriptionCVE.org

A vulnerability was detected in Tenda HG9 300001138. This affects an unknown part of the file /boaform/formPing of the component Diagnostic Ping Endpoint. Performing a manipulation of the argument pingAddr results in stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit is now public and may be used.

AnalysisAI

Stack-based buffer overflow in the Diagnostic Ping Endpoint of Tenda HG9 firmware allows unauthenticated remote attackers to achieve code execution by supplying a malicious pingAddr parameter. The vulnerability exists in the /boaform/formPing component and is exploitable over the network with low complexity. Public exploit code exists and no patch is currently available.

Technical ContextAI

Classified as CWE-119 (Buffer Overflow). Affects Hg9 Firmware. A vulnerability was detected in Tenda HG9 300001138. This affects an unknown part of the file /boaform/formPing of the component Diagnostic Ping Endpoint. Performing a manipulation of the argument pingAddr results in stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit is now public and may be used.

RemediationAI

Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible. Restrict network access to the affected service where possible.