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WAVLINK WN536AX6-A EUVDEUVD-2026-114908

| CVE-2026-120278 MEDIUM
Improper Authentication (CWE-287)
2026-11-02 cna@vuldb.com GHSA-v6ff-2mqg-mg4g
5.5
CVSS 4.0 · Vendor: vuldb
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach router management interface
  2. Exploit
    Send crafted request to /bin/ioos VPN handler
  3. Execution
    Manipulate 'opt' argument to bypass authentication
  4. Impact
    Read exposed VPN client list

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires network access to the router's management/web service exposing the VPN Client List Handler in /bin/ioos (functions sub_416d48/sub_41a7c0); the attacker manipulates the 'opt' argument on that endpoint to trigger the missing authentication check. Per the CVSS vector (AV:N/AC:L/PR:N/UI:N) no credentials, user interaction, or special configuration are stated as required against default deployments of the WAVLINK WN536AX6-A V260507_2.0.0. The practical limiting factors are the narrow impact (only the VPN client list is disclosed - no integrity or availability effect) and the need for the attacker to reach the device's service interface, which on consumer routers is typically LAN-facing unless remote management is enabled; the available sources do not state whether the endpoint is exposed on the WAN by default.

Impact

This is a genuine but moderate-priority issue, not a high-severity emergency. The supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N) describes a remote, low-complexity, unauthenticated authentication bypass, but the impact is narrow: VC:L with VI:N and VA:N means only limited confidentiality loss (disclosure of the VPN client list) with no integrity or availability impact, consistent with the CWE-287 classification and the 5.5 base score. The exploit maturity is E:P (proof-of-concept), and the vuln.today decision label is 'this_month' - not 'act_now' or 'emergency' - which aligns with a real-but-non-urgent fix timeline. No EPSS score is provided and the CVE is not listed in CISA KEV, so there is no confirmation of active exploitation despite the description stating the exploit is public. The main signals are consistent (network vector, no auth, low-value information-disclosure impact); the chief uncertainty is deployment scale and whether the public write-up constitutes working exploit code - verify against the referenced GitHub advisory.

Exploit ScenarioDerived

A remote attacker with network reachability to the router's management interface sends a crafted request to the VPN Client List Handler in /bin/ioos, manipulating the 'opt' argument to bypass the authentication check and read the configured VPN client list without credentials. A public PoC reference (a GitHub write-up) exists describing the request, though it is not verified as working exploit code. Exploitation requires no user interaction and succeeds against default configurations exposing the affected endpoint.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Nov 02, 2026

Missing authentication in the VPN Client List Handler of WAVLINK WN536AX6-A firmware V260507_2.0.0 lets remote attackers manipulate the 'opt' argument in /bin/ioos to disclose VPN client information without credentials. The disclosure states the exploit is now public and references a GitHub write-up, but no CISA KEV entry is indicated; the issue is confidentiality-only and moderate priority because the management service is typically LAN-facing unless remote management is enabled.

RemediationAI

No vendor-released patch is identified in the available data. Until WAVLINK publishes fixed firmware, restrict access to the router management/web service that exposes /bin/ioos and the VPN Client List Handler, particularly by not exposing the router web UI to untrusted networks and by disabling WAN-side remote management if it is enabled; disabling remote management prevents off-site administration as a trade-off. Check the VulDB entry https://vuldb.com/vuln/429622 and the CVE record for updated vendor guidance, and monitor for unauthorized access to VPN client information. Placing the router behind a firewall that blocks inbound access to its management service reduces exposure but does not correct the missing authentication check.

Affected VersionsENISA

WN536AX6-A V260507_2.0.0

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

The flaw is a CWE-287 missing-authentication weakness in the /bin/ioos binary of WAVLINK WN536AX6-A firmware, specifically in functions sub_416d48/sub_41a7c0 that implement the VPN Client List Handler. According to the disclosure, manipulating the 'opt' argument reaches functionality that should require authentication but does not, resulting in disclosure of VPN client information. The exact request format, the precise authentication check that is missing, and whether the handler is reachable from the WAN versus only the LAN are not described in the available sources; no CPE identifiers were provided.

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Severity by source

Vendor (vuldb) PRIMARY 5.5 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
vuln.today AI 5.3 MEDIUM

Remote unauthenticated access to the endpoint (AV:N/AC:L/PR:N/UI:N) yields only VPN-list disclosure, so C:L with I:N and A:N.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (vuldb).

CVSS VectorVendor: vuldb

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

A vulnerability was detected in WAVLINK WN536AX6-A V260507_2.0.0. Impacted is the function sub_416d48/sub_41a7c0 of the file /bin/ioos of the component VPN Client List Handler. Performing a manipulation of the argument opt results in missing authentication. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure.

Threat Intelligence Overview

EPSS Score
0.4%
Top 66% exploitable
Prevalence
Low
niche consumer WAVLINK router model, limited enterprise footprint
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GitHub VulDB

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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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