Author: Ameeba

Overview

A critical security vulnerability, identified as CVE-2025-6752, has been discovered affecting several Linksys router models, including WRT1900ACS, EA7200, EA7450, and EA7500 up to 20250619. This vulnerability has been classified as critical due to its potential to compromise systems and leak data. This vulnerability is particularly concerning as it affects the function SetDefaultConnectionService of the file /upnp/control/Layer3Forwarding of the IGD component and can be exploited remotely. The exploit is publicly disclosed, and the vendor has yet to respond.

Vulnerability Summary

CVE ID: CVE-2025-6752
Severity: Critical (8.8 CVSS score)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Linksys WRT1900ACS | Up to 20250619
Linksys EA7200 | Up to 20250619
Linksys EA7450 | Up to 20250619
Linksys EA7500 | Up to 20250619

How the Exploit Works

The vulnerability comes into play when an attacker manipulates the argument NewDefaultConnectionService, leading to a stack-based buffer overflow. This overflow then can cause the system to crash or, worse, allow the attacker to execute arbitrary code on the system. This exploitation can be initiated remotely, making it a significant threat to any unprotected networks.

Conceptual Example Code

Below is a conceptual example of how an HTTP request exploiting this vulnerability might look:

POST /upnp/control/Layer3Forwarding HTTP/1.1
Host: target_router_IP
Content-Type: application/xml; charset="utf-8"
SOAPAction: "urn:schemas-upnp-org:service:Layer3Forwarding:1#SetDefaultConnectionService"
<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>
<u:SetDefaultConnectionService xmlns:u="urn:schemas-upnp-org:service:Layer3Forwarding:1">
<NewDefaultConnectionService>[malicious_code]</NewDefaultConnectionService>
</u:SetDefaultConnectionService>
</s:Body>
</s:Envelope>

In this example, the [malicious_code] placeholder would be replaced with the actual code designed to overflow the buffer.

Recommended Mitigation

Until the vendor releases a patch to fix this vulnerability, users are advised to apply a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary mitigation. These solutions can help detect and block malicious activities related to this vulnerability. Furthermore, users should regularly monitor their network for any unusual activities.

Overview

A critical security vulnerability, dubbed CVE-2025-6751, has been detected in the Linksys E8450 up to version 1.2.00.360516. This vulnerability has garnered significant attention due to the dire potential consequences it can bring about, including system compromises and data leakage. The vulnerability resides in the HTTP POST Request Handler’s functionality, specifically the `set_device_language` function of the `portal.cgi` file. The malfunction occurs when the argument `dut_language` is manipulated, leading to a buffer overflow. Buffer overflow vulnerabilities are especially hazardous since they can allow an attacker to run arbitrary code on a victim’s system.

Vulnerability Summary

CVE ID: CVE-2025-6751
Severity: Critical, with a CVSS score of 8.8
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Linksys E8450 | Up to 1.2.00.360516

How the Exploit Works

The vulnerability arises from a buffer overflow condition in the `set_device_language` function of the `portal.cgi` file. In this case, when the `dut_language` argument is manipulated through a specially crafted HTTP POST request, it causes an overflow of the buffer. This overflow can potentially allow the attacker to overwrite important control data structures and execute arbitrary code, leading to a complete system compromise or data leakage.

Conceptual Example Code

Here’s a conceptual illustration of how the vulnerability might be exploited:

POST /portal.cgi HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
dut_language=<malicious_payload>

In the above example, “ would be replaced with a crafted string that exploits the buffer overflow vulnerability.

Mitigation

The most effective way to mitigate this vulnerability is by applying the vendor patch once it is available. However, in the absence of a vendor patch, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation. These systems can be configured to detect and block suspicious HTTP POST requests that aim to exploit this specific vulnerability. As always, it is also recommended to follow best practices for system and network security, including regular monitoring and updating of systems.

Overview

The cybersecurity landscape is continually evolving, with new vulnerabilities appearing frequently. One such vulnerability that has recently come to light is CVE-2025-6734. This critical vulnerability is found in UTT HiPER 840G up to version 3.1.1-190328 and poses a significant risk to users of this product.
The vulnerability affects the API component of the UTT HiPER 840G, specifically the function sub_484E40 of the file /goform/formP2PLimitConfig. The problem arises due to a manipulable argument leading to buffer overflow, which could potentially allow a remote attacker to compromise the system or leak sensitive data.

Vulnerability Summary

CVE ID: CVE-2025-6734
Severity: Critical, CVSS Severity Score 8.8
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise, data leakage

Affected Products

Product | Affected Versions

UTT HiPER 840G | up to 3.1.1-190328

How the Exploit Works

The vulnerability resides in the function sub_484E40 of the file /goform/formP2PLimitConfig in the API component of the UTT HiPER 840G. It stems from a buffer overflow condition that occurs when the ‘except’ argument is manipulated. This can lead to an overflow of the data buffer, and since the system does not correctly validate the size of the input, an attacker can overflow the buffer with arbitrary code.
This vulnerability can be exploited remotely without any user interaction or elevated privileges. Once the buffer overflow occurs, the attacker can execute arbitrary code with the privileges of the process, leading to system compromise or data leakage.

Conceptual Example Code

The following conceptual example illustrates a potential exploit scenario. Note that this is a simplified representation and actual exploitation would require more complex code.

POST /goform/formP2PLimitConfig HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
except=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...

In this example, the ‘except’ argument is overloaded with a large number of ‘A’ characters, which could overflow the buffer and potentially allow the execution of arbitrary code.
To mitigate this vulnerability, users are advised to apply the vendor’s patch as soon as it becomes available. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) may provide temporary mitigation against potential exploits.

Overview

The cybersecurity landscape is riddled with vulnerabilities that can potentially compromise systems, lead to data leakage, or facilitate malicious activities. One such vulnerability is the CVE-2025-6732, a critical buffer overflow vulnerability found in UTT HiPER 840G up to version 3.1.1-190328. This vulnerability is particularly concerning due to its severity and the potential for remote exploitation. It affects the API component of the router, specifically the strcpy function of /goform/setSysAdm file, and is a stark reminder of the importance of proactive cybersecurity measures.

Vulnerability Summary

CVE ID: CVE-2025-6732
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

UTT HiPER 840G | up to 3.1.1-190328

How the Exploit Works

The vulnerability lies in the buffer overflow potential of the strcpy function of /goform/setSysAdm file of the API component. By manipulating the argument passwd1, an attacker can cause the system to overflow the buffer, leading to potential system compromise. The attack can be initiated remotely, thus increasing the risk significantly. It is noteworthy that the exploit has been disclosed publicly, thereby increasing the possibility of its use in malicious activities.

Conceptual Example Code

An example of how the vulnerability might be exploited is presented below. This is a conceptual representation and should not be used for malicious purposes.

POST /goform/setSysAdm HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
passwd1= [Insert long string that causes buffer overflow]

Mitigation and Recommendations

While the vendor, UTT Technologies, has not yet issued a patch, it is highly recommended to apply vendor patches as soon as they become available. In the meantime, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used as temporary mitigation measures. Moreover, regular auditing of router configurations and continuous monitoring of network traffic can help identify any irregularities indicative of a potential exploit.
Furthermore, as a general rule, devices should be updated regularly to the latest firmware version to protect against known vulnerabilities, and default passwords should be changed to strong, unique passwords to reduce the risk of unauthorized access.

Overview

In the realm of cybersecurity, one cannot underestimate the importance of staying updated with the latest vulnerabilities. One such critical security flaw that requires immediate attention is CVE-2015-0843, a buffer overflow vulnerability in yubiserver before version 0.6. This vulnerability, with a high CVSS severity score of 9.8, poses a significant threat to all systems running a version of yubiserver prior to 0.6. If successfully exploited, this vulnerability could lead to system compromise and potential data leakage, causing substantial damage to the affected parties.

Vulnerability Summary

CVE ID: CVE-2015-0843
Severity: Critical (9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

yubiserver | Versions prior to 0.6

How the Exploit Works

The vulnerability CVE-2015-0843 is a buffer overflow vulnerability caused by the incorrect usage of the sprintf function in yubiserver before 0.6. In essence, sprintf writes data into a buffer without checking if the buffer can hold the data. If the data is larger than the buffer, it will overflow into adjacent memory, overwriting whatever was there. An attacker can exploit this to execute arbitrary code or disrupt the normal functioning of the system, possibly leading to system compromise or data leakage.

Conceptual Example Code

Here is a conceptual example of how an attacker might exploit the vulnerability. The attacker sends a specially crafted payload that causes buffer overflow when processed by the vulnerable yubiserver function.

#include <string.h>
int main() {
char buffer[500];
char payload[1000];
// Fill payload with a large amount of data
memset(payload, 'A', sizeof(payload)-1);
payload[sizeof(payload)-1] = '\0';
// Simulate the misuse of sprintf
sprintf(buffer, "%s", payload);
return 0;
}

This code overflows the buffer with ‘A’ characters, leading to a buffer overflow. In real-world scenarios, an attacker would replace the ‘A’ characters with malicious code, potentially leading to system compromise.