EW-7438RPn 1.31 — CraftedSignal Threat Feed

Edimax EW-7438RPn Stack-Based Buffer Overflow Vulnerability (CVE-2026-9481)

hello@craftedsignal.io — Tue, 26 May 2026 14:48:18 +0000

A critical stack-based buffer overflow vulnerability, identified as CVE-2026-9481, has been discovered in Edimax EW-7438RPn version 1.31. This vulnerability resides within the formStats function located in the /goform/formStats file. The vulnerability stems from improper input validation of the submit-url argument, allowing a remote attacker to potentially overwrite parts of the stack. Publicly available exploit code exists, increasing the risk of widespread exploitation. The vendor was notified but did not respond, increasing the urgency for users to apply mitigations.

Attack Chain

The attacker sends a specially crafted HTTP request to the Edimax EW-7438RPn device.
The HTTP request targets the /goform/formStats endpoint.
The request includes the submit-url argument with a value exceeding the expected buffer size.
The formStats function processes the submit-url argument without proper bounds checking.
The excessive length of the submit-url argument causes a buffer overflow on the stack.
The attacker overwrites critical data on the stack, such as the return address.
Upon function return, control is redirected to an address specified by the attacker.
The attacker executes arbitrary code on the device, potentially gaining full control.

Impact

Successful exploitation of CVE-2026-9481 allows a remote attacker to execute arbitrary code on the vulnerable Edimax EW-7438RPn device. Given the device’s likely placement as a network gateway or access point, this could lead to complete compromise of the network, data exfiltration, or denial-of-service conditions. The number of affected devices is unknown, but the existence of public exploit code increases the likelihood of widespread attacks targeting this vulnerability.

Recommendation

Deploy the Sigma rule “Detect CVE-2026-9481 Exploitation Attempt via Long submit-url” to identify potential exploitation attempts in web server logs.
Monitor webserver logs for abnormal POST requests to the /goform/formStats endpoint, looking for unusually long submit-url parameters.
Apply network intrusion detection rules that look for patterns indicative of buffer overflow attempts in HTTP requests targeting Edimax EW-7438RPn devices.

Edimax EW-7438RPn Stack-Based Buffer Overflow Vulnerability (CVE-2026-9479)

hello@craftedsignal.io — Tue, 26 May 2026 14:39:49 +0000

A stack-based buffer overflow vulnerability, tracked as CVE-2026-9479, has been identified in Edimax EW-7438RPn version 1.31. The vulnerability resides within the formLogout function of the /goform/formLogout file. By manipulating the submit-url argument, a remote attacker can trigger a buffer overflow, potentially leading to arbitrary code execution. Publicly available exploit code exists for this vulnerability. The vendor was notified but did not respond to the disclosure. This vulnerability poses a significant risk to devices exposed to untrusted networks.

Attack Chain

Attacker identifies an Edimax EW-7438RPn device running firmware version 1.31.
Attacker crafts a malicious HTTP request targeting the /goform/formLogout endpoint.
The crafted request includes a submit-url argument with a string exceeding the buffer’s capacity.
The formLogout function processes the submit-url argument without proper bounds checking.
The excessive data overwrites memory on the stack, including the return address.
The function attempts to return, but the overwritten return address redirects execution to attacker-controlled code.
Attacker gains arbitrary code execution on the device.
Attacker leverages code execution to establish persistence or further compromise the network.

Impact

Successful exploitation of this vulnerability allows a remote attacker to execute arbitrary code on the Edimax EW-7438RPn device. This could lead to a complete compromise of the device, including data exfiltration, modification of device settings, or use of the device as a bot in a larger attack. Given the lack of vendor response, affected devices remain vulnerable.

Recommendation

Monitor web server logs for POST requests to /goform/formLogout with abnormally long submit-url parameters using the Sigma rule provided below.
Implement web application firewall (WAF) rules to block requests containing excessively long submit-url parameters to /goform/formLogout.
Since the vendor has not provided a patch, consider replacing the affected Edimax EW-7438RPn devices.

Edimax EW-7438RPn Stack-Based Buffer Overflow Vulnerability (CVE-2026-9463)

hello@craftedsignal.io — Tue, 26 May 2026 14:39:34 +0000

CVE-2026-9463 describes a stack-based buffer overflow vulnerability affecting Edimax EW-7438RPn version 1.31. The vulnerability resides in the formLicence function within the /goform/formLicence file. A remote attacker can trigger this vulnerability by manipulating the submit-url argument, potentially leading to arbitrary code execution. The vendor has been notified but has not responded. Publicly available exploit code exists, increasing the risk of exploitation. This vulnerability matters to defenders because it allows unauthenticated attackers to compromise the device remotely, potentially gaining control of the network it serves.

Attack Chain

The attacker sends a crafted HTTP request to the /goform/formLicence endpoint of the Edimax EW-7438RPn device.
The request includes a malicious submit-url argument containing a string longer than the allocated buffer size within the formLicence function.
The device processes the HTTP request and calls the formLicence function with the attacker-controlled submit-url argument.
Due to insufficient bounds checking, the oversized submit-url argument overwrites the stack buffer.
The attacker precisely crafts the overflow to overwrite critical data on the stack, such as the return address.
The formLicence function completes its execution and attempts to return.
Instead of returning to the legitimate caller, the overwritten return address redirects execution to attacker-controlled code.
The attacker gains arbitrary code execution on the device, potentially leading to full system compromise.

Impact

Successful exploitation of CVE-2026-9463 allows a remote attacker to execute arbitrary code on the Edimax EW-7438RPn device. Given the nature of buffer overflows, this can result in complete system compromise, allowing the attacker to control the device, potentially pivot to other devices on the network, and intercept or manipulate network traffic. The vulnerability affects Edimax EW-7438RPn version 1.31. The number of affected devices is unknown, but exploitation could lead to widespread disruption of home and small business networks.

Recommendation

Deploy the Sigma rule Detect CVE-2026-9463 Exploitation Attempt to detect malicious HTTP requests targeting the vulnerable endpoint and argument.
Monitor web server logs for suspicious requests to /goform/formLicence containing unusually long submit-url parameters to identify potential exploitation attempts.
Since no patch is available, consider replacing the affected Edimax EW-7438RPn device with a more secure alternative.

Edimax EW-7438RPn Stack-Based Buffer Overflow Vulnerability (CVE-2026-9462)

hello@craftedsignal.io — Tue, 26 May 2026 14:21:47 +0000

A stack-based buffer overflow vulnerability, identified as CVE-2026-9462, affects Edimax EW-7438RPn version 1.31. The vulnerability resides within the formWpsProxyEnable function of the /goform/formWpsProxyEnable file. By manipulating the submit-url argument, a remote attacker can trigger a buffer overflow, potentially leading to arbitrary code execution. According to the NVD advisory published on May 25, 2026, a public exploit is available, increasing the risk of exploitation. The vendor was notified about this vulnerability, but has not responded. This vulnerability poses a significant threat to devices running the affected firmware version.

Attack Chain

Attacker identifies an Edimax EW-7438RPn device running firmware version 1.31.
Attacker crafts a malicious HTTP request targeting the /goform/formWpsProxyEnable endpoint.
The malicious request includes a submit-url argument with a payload exceeding the buffer size allocated for it within the formWpsProxyEnable function.
The formWpsProxyEnable function processes the request without proper bounds checking on the submit-url argument.
The oversized submit-url payload overwrites memory on the stack, including the return address.
The function attempts to return, but instead jumps to an address controlled by the attacker, allowing for code execution.
The attacker executes arbitrary commands on the device.
The attacker gains full control of the device, potentially using it for malicious purposes such as botnet participation, data exfiltration, or pivoting to other network resources.

Impact

Successful exploitation of CVE-2026-9462 allows a remote attacker to execute arbitrary code on the affected Edimax EW-7438RPn device. This could lead to complete device compromise, allowing the attacker to modify device settings, intercept network traffic, or use the device as a launchpad for further attacks within the network. Given the availability of a public exploit, the risk of widespread exploitation is elevated.

Recommendation

Monitor web server logs for requests targeting the /goform/formWpsProxyEnable endpoint with abnormally long submit-url arguments to detect exploitation attempts using the Sigma rule provided.
Apply network intrusion detection system (IDS) rules to detect and block malicious HTTP requests targeting the vulnerable endpoint.
Although no patch is available, consider isolating vulnerable Edimax EW-7438RPn devices from critical network segments to limit the potential impact of a successful exploit.

Edimax EW-7438RPn Stack-Based Buffer Overflow Vulnerability (CVE-2026-9459)

hello@craftedsignal.io — Tue, 26 May 2026 14:12:18 +0000

A stack-based buffer overflow vulnerability, identified as CVE-2026-9459, affects the Edimax EW-7438RPn version 1.31. The vulnerability resides within the formConnectionSetting function located in the /goform/formConnectionSetting file. Successful exploitation allows a remote attacker to potentially execute arbitrary code on the device. The root cause is improper input validation on the max_Conn and timeOut arguments, leading to a buffer overflow when these arguments are manipulated. Publicly available exploit code exists, increasing the risk of widespread exploitation. The vendor has been unresponsive to disclosure attempts.

Attack Chain

The attacker identifies a vulnerable Edimax EW-7438RPn 1.31 device exposed to the internet.
The attacker crafts a malicious HTTP request targeting the /goform/formConnectionSetting endpoint.
Within the HTTP request, the attacker manipulates the max_Conn or timeOut arguments with an overly long string.
The vulnerable formConnectionSetting function processes the request without proper bounds checking.
The oversized input overflows the stack buffer, overwriting adjacent memory regions.
The attacker carefully crafts the overflow to overwrite the return address with the address of malicious code.
The function returns, diverting execution to the attacker-controlled code.
The attacker achieves arbitrary code execution on the device, potentially gaining full control.

Impact

Successful exploitation of CVE-2026-9459 can lead to complete compromise of the Edimax EW-7438RPn device. This could allow attackers to reconfigure the device, intercept network traffic, or use the device as a foothold for further attacks on the local network. Given the widespread use of such devices, a significant number of home and small business networks could be affected. The lack of vendor response makes patching unlikely, extending the window of vulnerability.

Recommendation

Apply web application firewall rules to filter requests to /goform/formConnectionSetting containing excessively long max_Conn or timeOut parameters, mitigating exploitation attempts.
Monitor web server logs (category webserver) for POST requests to /goform/formConnectionSetting with unusually long cs-uri-query parameters, corresponding to potential buffer overflow attempts.
Deploy the Sigma rule “Detect CVE-2026-9459 Exploitation Attempt” to detect suspicious requests exploiting this vulnerability.
Consider replacing affected Edimax EW-7438RPn devices with patched or more secure alternatives, given the lack of vendor support.

CVE-2026-9426 - Edimax EW-7438RPn Stack-Based Buffer Overflow

hello@craftedsignal.io — Tue, 26 May 2026 14:07:20 +0000

A stack-based buffer overflow vulnerability, identified as CVE-2026-9426, affects Edimax EW-7438RPn version 1.31. This flaw resides within the formHwSet function of the /goform/formHwSet file. The vulnerability is triggered through the manipulation of several arguments including Anntena, Mcs, regDomain, nic0Addr, nic1Addr, wlanAddr, wanAddr, wlanSSID, wlanChan, initgain, txcck, txofdm, and submit-url. A remote attacker can exploit this vulnerability to potentially execute arbitrary code on the affected device. Public exploits are available, increasing the risk of exploitation. The vendor was notified but has not responded.

Attack Chain

The attacker identifies an Edimax EW-7438RPn device running firmware version 1.31 accessible over the network.
The attacker crafts a malicious HTTP request targeting the /goform/formHwSet endpoint.
Within the HTTP request, the attacker includes a long string in one or more of the vulnerable parameters: Anntena, Mcs, regDomain, nic0Addr, nic1Addr, wlanAddr, wanAddr, wlanSSID, wlanChan, initgain, txcck, txofdm, or submit-url.
The device processes the HTTP request, passing the attacker-controlled input to the formHwSet function without proper bounds checking.
The oversized input overflows the stack buffer allocated for the affected parameter(s).
The stack overflow overwrites critical data, including the return address, on the stack.
The attacker redirects control to an attacker-controlled address.
The attacker executes arbitrary code on the device, potentially gaining full control.

Impact

Successful exploitation of this vulnerability allows a remote attacker to execute arbitrary code on the Edimax EW-7438RPn device. This could lead to complete compromise of the device, allowing the attacker to eavesdrop on network traffic, modify device settings, or use the device as a launchpad for further attacks on the internal network. Given the nature of the vulnerability and the lack of vendor response, many devices may be vulnerable.

Recommendation

Deploy the Sigma rule Detect CVE-2026-9426 Exploitation Attempt via Long URI to detect potential exploitation attempts by identifying abnormally long request parameters (cs-uri-query) targeting the vulnerable endpoint.
Implement rate limiting on requests to the /goform/formHwSet endpoint to mitigate brute-force exploitation attempts (log source: webserver).
Monitor web server logs for POST requests with unusually long parameters related to Anntena, Mcs, regDomain, nic0Addr, nic1Addr, wlanAddr, wanAddr, wlanSSID, wlanChan, initgain, txcck, txofdm, or submit-url in the URI (log source: webserver).