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Edimax EW-7438RPn CVE-2026-9459

| EUVDEUVD-2026-31675 HIGH
Stack-based Buffer Overflow (CWE-121)
2026-05-25 VulDB GHSA-hwrg-8cjq-3gj6
7.4
CVSS 4.0 · Vendor: VulDB
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Attack ChainAIDerived

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

  1. Recon
    Reach device web UI on LAN
  2. Delivery
    Authenticate with low-privilege admin credentials
  3. Exploit
    POST oversized max_Conn/timeOut to /goform/formConnectionSetting
  4. Install
    Overflow stack buffer in formConnectionSetting
  5. C2
    Hijack saved return address
  6. Execute
    Execute code as web server on device
  7. Impact
    Pivot or intercept LAN traffic

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

Attacker must be able to reach the device's HTTP management interface on the network and possess low-level credentials (CVSS PR:L) sufficient to invoke /goform/formConnectionSetting; no user interaction is required. Exploitation is specifically limited to Edimax EW-7438RPn firmware 1.31 and requires sending crafted max_Conn or timeOut parameters to the formConnectionSetting handler. Practical limits include the device's typical LAN-only management exposure and the need for valid admin authentication, which together constrain mass exploitation but do not protect against insiders, default-credential deployments, or attackers who have already reached the LAN.

Impact

CVSS 4.0 rates this 7.4 (High) with vector AV:N/AC:L/AT:N/PR:L/UI:N and VC:H/VI:H/VA:H, indicating a network-reachable, low-complexity attack that requires some level of authentication and yields full confidentiality, integrity, and availability impact on the device. EPSS is very low at 0.04% (13th percentile), and the CVE is not on CISA KEV, but a public POC exists on GitHub and SSVC classifies the technical impact as 'total' with exploitation status 'poc' and automatable 'no'. The PR:L requirement (likely a web admin credential) and the niche consumer-extender footprint plausibly explain the low EPSS despite total technical impact - meaningful risk concentrates on devices with default/weak credentials or exposed management interfaces, rather than mass exploitation.

Exploit ScenarioDerived

An attacker on the same LAN (or who has reached the management interface via a misconfigured remote-admin setting) authenticates with default or weak admin credentials and sends a crafted POST to /goform/formConnectionSetting with an oversized max_Conn or timeOut value, smashing the stack and hijacking control flow of the web server. Because a public POC at https://github.com/wudipjq/my_vuln/blob/main/Edimax/vuln_12/12.md documents the trigger, weaponization for code execution on the embedded device is straightforward, enabling persistent foothold for traffic interception or pivot into the internal network.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Jun 08, 2026

Stack-based buffer overflow in the Edimax EW-7438RPn 1.31 wireless range extender allows remote attackers with low privileges to corrupt memory by sending crafted max_Conn or timeOut parameters to /goform/formConnectionSetting. Publicly available exploit code exists, and the vendor did not respond to coordinated disclosure, leaving deployed devices unpatched. EPSS probability is low (0.04%), but the combination of public POC, network reachability, and full CIA impact warrants prompt action on exposed devices.

RemediationAI

No vendor-released patch identified at time of analysis, as Edimax did not respond to the reporter. As compensating controls, restrict access to the device's web management interface to trusted management VLANs or hosts and disable any WAN-side/remote administration option (trade-off: legitimate remote management becomes unavailable), enforce strong unique admin credentials since exploitation requires PR:L authentication, and place the extender behind a segmented SSID/VLAN to limit who can reach /goform/formConnectionSetting. Where feasible, replace the EW-7438RPn with a supported model, as continued use of an end-of-support device with public exploit code and no vendor response represents ongoing risk; monitor https://vuldb.com/vuln/365440 and https://nvd.nist.gov/vuln/detail/CVE-2026-9459 for any future firmware update.

Affected VersionsENISA

EW-7438RPn 1.31

Affected Packages

euvd ew_7438rpn no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The Edimax EW-7438RPn is a consumer/SOHO Wi-Fi range extender whose web management interface exposes /goform/ endpoints implemented in native code. The vulnerable handler formConnectionSetting fails to bound-check the max_Conn and timeOut parameters before copying them into a fixed-size stack buffer, matching CWE-121 (Stack-based Buffer Overflow). On embedded MIPS/ARM router firmware, such overflows typically overwrite the saved return address and can lead to arbitrary code execution as the web server process, which generally runs with high privileges on the device.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulDB) PRIMARY 7.4 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Primary rating from Vendor (VulDB) · only source for this CVE.

CVSS VectorVendor: VulDB

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

Lifecycle Timeline

1
CVSS changed
May 26, 2026 - 19:37 NVD
8.8 (HIGH) 7.4 (HIGH)

DescriptionCVE.org

A security flaw has been discovered in Edimax EW-7438RPn 1.31. This affects the function formConnectionSetting of the file /goform/formConnectionSetting. Performing a manipulation of the argument max_Conn/timeOut results in stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Executive ViewAI

Why It Matters

Edimax EW-7438RPn wireless range extenders (firmware 1.31) are vulnerable to remote exploitation that could disrupt device operation, intercept network traffic, or enable attacker access to the network. Publicly available exploit code exists, the vendor has not released patches, and these devices are widely deployed in enterprise networks.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict network access via firewall blocking of /goform/formConnectionSetting requests, disable remote management features if available, implement network segmentation to isolate affected devices from internet access, and accelerate replacement with patched alternatives.

Threat Intelligence Overview

EPSS Score
0.0%
Top 87% exploitable
Exploit
POC
Public exploit code exists
Data Quality
7 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 HIGH
CISA KEV No
Public POC Yes
EPSS 0.0%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

57
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +37
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

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.

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