Tenda PW201A
CVE-2026-36803
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessIdentify Tenda PW201A on network
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DeliveryReach web admin HTTP interface
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ExploitSend crafted request to qossetting with oversized page parameter
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ExecutionOverflow buffer in httpd
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PersistCrash web server / reboot device
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ImpactSustained network outage
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
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 | Attacker must be able to reach the Tenda PW201A v1.0.5 web administration HTTP interface and send a request to the qossetting handler with an oversized page parameter - typically meaning LAN-adjacent access (rogue Wi-Fi client, compromised host on the network) or, in misconfigured deployments, a WAN-exposed admin port. The CVSS vector asserts PR:N (no authentication), but the description does not explicitly confirm the qossetting endpoint is reachable pre-login, so unauthenticated exploitability against a default configuration should be verified against the actual firmware. Exploitation is limited to this specific model and firmware (PW201A v1.0.5) and yields only denial of service, not code execution or data disclosure. |
| Impact | Signals are mixed but lean toward low real-world priority. CVSS 7.5 is driven entirely by the High availability impact with no confidentiality or integrity loss (C:N/I:N/A:H) - consistent with a pure DoS, not code execution. EPSS at 0.02% (4th percentile) and the absence of any CISA KEV listing indicate no observed mass exploitation. The CVSS vector (AV:N/AC:L/PR:N/UI:N) implies network-reachable, unauthenticated exploitation, but for a SOHO router this in practice usually means an attacker already on the LAN or one reaching an exposed WAN-side admin interface - a configuration most ISPs and users do not enable by default. Note also that the description does not state whether the overflow is reachable pre-authentication on the web UI; the CVSS PR:N assertion should be verified against the actual qossetting handler, as many Tenda endpoints require a session cookie. The research-repo reference is a finding artifact, not a weaponized PoC, so treat 'exploit code' status as unconfirmed. |
| Exploit ScenarioDerived | An attacker on the same LAN as the router (or reaching an exposed WAN admin interface) sends a single HTTP request to the qossetting endpoint with an oversized page parameter, overflowing the buffer and crashing the embedded web server or rebooting the device. Repeating the request creates a persistent denial of service, knocking the network offline until the device recovers or is power-cycled. No weaponized public PoC is identified, only a research repository documenting the finding. |
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Alert meAnalysisAIv1 – Jun 10, 2026
Denial of service in Tenda PW201A v1.0.5 routers allows remote unauthenticated attackers to crash the device by sending a crafted HTTP request that overflows a buffer in the page parameter of the qossetting function. EPSS is very low (0.02%, 4th percentile) and no public exploit identified at time of analysis beyond a research repository, but the CVSS 7.5 (AV:N/AC:L/PR:N/UI:N/A:H) reflects easy network reachability against the router's web management interface. The flaw is not in CISA KEV.
RemediationAI
No vendor-released patch identified at time of analysis - Tenda has not published an advisory or fixed firmware for CVE-2026-36803 in the supplied data. Until a firmware update is released, restrict access to the router's web administration interface: disable remote/WAN-side management entirely (most Tenda models expose this as 'Remote Web Management' and it should be Off), and on the LAN side limit admin UI access to a management VLAN or a small set of trusted IPs via the router's access-control list, accepting the trade-off that legitimate admins must connect from those sources. Where feasible, replace the PW201A with a supported model, since SOHO Tenda devices frequently accumulate unpatched httpd bugs of this class. Monitor the vendor page at tendacn.com for firmware later than v1.0.5 and the researcher reference https://github.com/xhh0124/SemVulLLM/tree/main/PW201A/qossetting for any proof-of-concept updates.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Tenda PW201A is a SOHO wireless router/access point; the qossetting function is part of its HTTP-based web administration interface that handles Quality-of-Service configuration. The root cause is CWE-120 (Classic Buffer Overflow / Buffer Copy without Checking Size of Input): the page parameter supplied in an HTTP request is copied into a fixed-size stack or heap buffer without bounds validation, corrupting adjacent memory and crashing the embedded httpd. The referenced researcher repository (SemVulLLM/PW201A/qossetting) suggests the issue was discovered via LLM-assisted firmware analysis of the router's web server binary. The CPE string in the input is a placeholder (cpe:2.3:a:n/a:n/a:*) and does not include a proper hardware/firmware CPE for the PW201A, limiting machine-readable inventory matching.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from Vendor (mitre) · only source for this CVE.
CVSS VectorVendor: mitre
Lifecycle Timeline
2DescriptionCVE.org
Shenzhen Tenda Technology Co., Ltd Tenda PW201A v1.0.5 was discovered to contain a buffer overflow in the page parameter of the qossetting function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request.
Executive ViewAI
A denial-of-service vulnerability in Tenda PW201A v1.0.5 routers (CVE-2026-36803) allows unauthenticated remote attackers to crash affected devices via a crafted HTTP request, creating network availability risk. Organizations deploying this router model face potential service disruptions affecting connectivity and network management operations. No vendor patch is currently available, requiring immediate compensating controls to restrict access to the vulnerable management interface.
Restrict network access to the HTTP management interface via firewall rules, limiting connections to trusted administrative sources. Disable remote management access if operationally feasible. Implement network segmentation isolating the router from untrusted networks. Monitor affected devices for anomalous HTTP requests or unexpected restarts indicating exploitation attempts.
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.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
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