CVE-2024-0539VulnerabilityPublished 15 Jan 2024Updated 3 Jun 2025

CVE-2024-0539: Tenda W9 · Stack-based Buffer Overflow

Affects Tenda W9Source CVE Database V5

Not known to be exploited · CVSS 8.8 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

8.8High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.3% chance of exploitation in 30 days – higher than 70% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Given the absence of official patches, European organizations should take immediate and specific actions: 1) Identify and inventory all Tenda W9 devices within their networks to assess exposure. 2) Isolate affected devices on segmented network zones with strict access controls to limit potential lateral movement. 3) Disable or restrict remote management interfaces and services, especially those accessible from untrusted networks, to reduce attack vectors. 4) Monitor network traffic for anomalous patterns indicative of exploitation attempts targeting the ssidIndex parameter or unusual httpd activity. 5) Where possible, replace Tenda W9 routers with alternative devices from vendors with active security support and patch management. 6) Employ network-level protections such as intrusion detection/prevention systems (IDS/IPS) configured to detect buffer overflow exploit signatures. 7) Educate IT staff about this vulnerability to ensure rapid response to any suspicious activity. 8) Regularly review vendor communications for any forthcoming patches or advisories. These steps go beyond generic advice by focusing on network segmentation, active monitoring, and device replacement strategies tailored to this specific vulnerability and product.

Description

A vulnerability was found in Tenda W9 1.0.0.7(4456) and classified as critical. This issue affects the function formQosManage_user of the component httpd. The manipulation of the argument ssidIndex leads to stack-based buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-250709 was assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

Impact

For European organizations, especially small and medium enterprises (SMEs) and home office users relying on Tenda W9 routers, this vulnerability poses a significant risk. Successful exploitation could lead to unauthorized network access, data exfiltration, and disruption of business operations. Given the router's role as a network gateway, compromise could facilitate lateral movement within corporate networks, undermining confidentiality and integrity of sensitive information. Additionally, availability could be impacted by denial-of-service conditions or device bricking. The lack of vendor response and patches exacerbates the risk, as organizations cannot rely on official fixes and must implement alternative mitigations. The threat is particularly relevant in sectors with high reliance on secure network infrastructure, such as finance, healthcare, and critical infrastructure, where data breaches or service disruptions have severe consequences. Moreover, the remote exploitability without user interaction increases the attack surface, making automated or mass exploitation campaigns plausible.

CWE-121Stack-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #14
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Implementation
Implement and perform bounds checking on input.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 3 Jul 2025, 21:42 UTC

WeaknessesCWE-121

Technical details

References

Community reviews

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