Tenda O3 Router
CVE-2026-36783
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessScan for exposed Tenda O3 admin HTTP
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DeliveryCraft HTTP request with oversized domain parameter
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ExploitSend to fromNetToolGet endpoint
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ExecutionOverflow stack buffer in httpd
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ImpactCrash web service and disrupt routing
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | The Tenda O3 web management HTTP service must be network-reachable by the attacker, and the target must be running firmware v1.0.0.5(4180); no authentication is required (CVSS PR:N) and no user interaction is needed (UI:N). The exploit specifically targets the fromNetToolGet handler reached via the device's network-diagnostic web functionality, so deployments that block WAN-side access to the admin HTTP port or place the router behind an upstream firewall ACL are not reachable. Limiting factors: impact is restricted to availability of the single router (crash/reboot), exploitation requires direct HTTP connectivity to the management interface (commonly LAN-only in default configurations), and only this specific firmware build has been confirmed vulnerable. |
| Impact | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/C:N/I:N/A:H, score 7.5) reflects unauthenticated network reachability with only availability impact, which is consistent with the DoS-only description. EPSS is extremely low (0.01%, 2nd percentile), and the vulnerability is not on the CISA KEV list, indicating no observed mass exploitation. However, CISA SSVC labels it as 'Exploitation: poc, Automatable: yes, Technical Impact: partial,' which raises the prioritization for defenders running exposed devices because PoC code exists and a crash can be triggered repeatedly with simple scripting. The honest read: this is a low-urgency issue for most enterprises but meaningful for ISPs and small-business deployments that expose the Tenda O3 web UI to the WAN, where repeated DoS can be operationally disruptive. A potential caveat is that CWE-121 stack overflows on embedded routers sometimes permit code execution beyond the documented DoS; the public PoC has not been independently validated for RCE, so the A:H-only impact should be treated as the floor, not necessarily the ceiling. |
| Exploit ScenarioDerived | An attacker scans the internet for Tenda O3 routers exposing their web management interface on the WAN, then sends a single HTTP request to the network-tools endpoint with an oversized 'domain' parameter value. The stack buffer overflow in fromNetToolGet corrupts the saved return address and crashes the httpd process, taking the management plane (and on many embedded routers, routing/NAT) offline until the device watchdog reboots. A publicly available proof-of-concept exists in the referenced GitHub repository, lowering the skill bar for automated mass-scanning DoS campaigns. |
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Alert meAnalysisAIv1 – Jun 10, 2026
Denial-of-service via stack buffer overflow affects the Tenda O3 wireless router firmware v1.0.0.5(4180), where the fromNetToolGet handler fails to bound-check the domain parameter supplied in HTTP requests. Remote attackers can crash the router's web management service by sending a crafted request, disrupting network connectivity for downstream clients. SSVC flags the issue as proof-of-concept with automatable exploitation and partial technical impact, though EPSS remains low at 0.01% and no in-the-wild exploitation has been confirmed.
RemediationAI
No vendor-released patch identified at time of analysis; Tenda has not published a fixed firmware version in the available references. As compensating controls, restrict access to the router's HTTP management interface so it is reachable only from trusted LAN segments - disable WAN-side remote management entirely via the device admin UI, which is the highest-impact mitigation and has minimal trade-off for residential/SOHO use. Where remote administration is required, place the management interface behind a VPN or source-IP ACL on an upstream firewall to block untrusted HTTP requests targeting the fromNetToolGet endpoint; this preserves admin capability at the cost of added connection setup. Monitor the device for unexpected reboots or web-UI unavailability as a detection signal, and consult https://github.com/xhh0124/SemVulLLM/tree/main/O3/fromNetToolGet for the PoC payload shape to build IDS/WAF signatures matching oversized 'domain' parameters to /goform/ or equivalent network-tool endpoints.
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Technical ContextAI · show details
The Tenda O3 is a SOHO/outdoor wireless CPE router whose embedded web administration server exposes a network diagnostic endpoint backed by the fromNetToolGet function. CWE-121 (Stack-based Buffer Overflow) describes the root cause: the function copies the user-controlled 'domain' HTTP parameter into a fixed-size stack buffer without length validation, allowing the saved return address and adjacent stack frame to be overwritten. On the MIPS/ARM-class SoCs typical of Tenda CPE devices, this corruption typically crashes the httpd/goahead-style web server process; while CWE-121 can sometimes be escalated to code execution, the public research (referenced GitHub PoC by xhh0124/SemVulLLM) only demonstrates a denial-of-service crash. The CPE entry of 'cpe:2.3:a:n/a:n/a:*' is a placeholder and does not properly enumerate the affected hardware/firmware tuple.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Unauthenticated HTTP request to network-reachable admin interface (AV:N/AC:L/PR:N/UI:N); described impact is process crash only, so C:N/I:N and A:H.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
2DescriptionCVE.org
Shenzhen Tenda Technology Co., Ltd Tenda O3 Wireless Router v1.0.0.5(4180) was discovered to contain a stack overflow in the domain parameter of the fromNetToolGet function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request.
Executive ViewAI
Tenda O3 wireless routers running firmware v1.0.0.5(4180) are vulnerable to unauthenticated remote denial-of-service attacks that crash the web management service, disrupting network administrative access and potentially downstream client connectivity. Publicly available exploit code exists with no vendor patch currently released, creating immediate operational risk. Any organization operating these routers faces potential unplanned network downtime without interim mitigations.
No vendor-released patch identified at time of analysis. Interim mitigations: (1) Restrict network access to management interface (ports 80/443) via firewall rules and VLAN segmentation to administrative networks only; (2) Disable remote management features if operationally feasible; (3) Implement automated monitoring and restart mechanisms for router availability; (4) Maintain out-of-band access (console/physical access) for manual recovery if web management interface is compromised.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
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