Overview
CVE-2025-60684 is a medium-severity vulnerability affecting specific versions of ToToLink routers. This vulnerability allows an unauthenticated attacker to potentially execute arbitrary code or cause memory corruption due to a stack buffer overflow in the web interface.
Technical Details
The vulnerability resides within the cstecgi.cgi binary, specifically the sub_42F32C function. The web interface processes the “lang” parameter, using it to construct Help URL strings. The sprintf() function is used to build these strings into fixed-size stack buffers. However, there’s a critical lack of input validation on the length of the “lang” parameter. A maliciously crafted, overly long “lang” value can overflow these buffers, overwriting adjacent memory on the stack. This overflow can be exploited to overwrite crucial data, including return addresses, potentially allowing the attacker to redirect execution flow and execute arbitrary code.
Affected Devices:
- ToToLink LR1200GB (V9.1.0u.6619_B20230130)
- ToToLink NR1800X (V9.1.0u.6681_B20230703)
CVSS Analysis
The vulnerability has been assigned a CVSS score of 6.5, indicating a MEDIUM severity. The CVSS vector reflects the following characteristics:
- Attack Vector (AV): Network (N) – The vulnerability can be exploited over the network.
- Attack Complexity (AC): Low (L) – The conditions for successful exploitation are relatively straightforward.
- Privileges Required (PR): None (N) – No authentication is required to exploit the vulnerability.
- User Interaction (UI): None (N) – No user interaction is required to trigger the vulnerability.
- Scope (S): Unchanged (U) – An exploited vulnerability can only affect resources managed by the same security authority.
- Confidentiality Impact (C): Low (L) – There is limited information disclosure.
- Integrity Impact (I): Low (L) – There is limited modification of data.
- Availability Impact (A): Low (L) – There is limited disruption of services.
Possible Impact
Successful exploitation of this vulnerability can have several negative consequences:
- Arbitrary Code Execution: An attacker could potentially execute arbitrary code on the router, gaining full control of the device.
- Memory Corruption: The overflow can corrupt memory, leading to unpredictable behavior or denial of service.
- Device Compromise: A compromised router can be used as a launchpad for further attacks on the local network.
- Data Theft: Depending on the attacker’s objectives and the level of access gained, sensitive data stored on or passing through the router could be compromised.
Mitigation and Patch Steps
The most effective mitigation is to apply the official patch or firmware update provided by ToToLink, if available. Users should regularly check the ToToLink website for security updates.
Until a patch is available, consider the following temporary workarounds:
- Disable Remote Administration: If possible, disable remote administration of the router to limit the attack surface.
- Network Segmentation: Segment your network to isolate the router from critical resources.
- Monitor Network Traffic: Monitor network traffic for suspicious activity originating from the router.
Important: It is strongly advised to upgrade the firmware as soon as an official patch is released. Check the official ToToLink website for updates.