Full Report
Stack-based Buffer Overflow vulnerability (CVE-2026-44089) has been found in Totolink EX1200L router software.
Analysis Summary
# Vulnerability: Stack-based Buffer Overflow in Totolink EX1200L
## CVE Details
- **CVE ID:** CVE-2026-44089
- **CVSS Score:** Not explicitly listed in the report (Typically High/Critical for unauthenticated RCE)
- **CWE:** CWE-121 (Stack-based Buffer Overflow)
## Affected Systems
- **Products:** Totolink EX1200L router
- **Versions:** 9.3.5u.6146_B20201023 (Confirmed); other versions may also be affected.
- **Configurations:** Default login functionality.
## Vulnerability Description
A stack-based buffer overflow exists within the `cgi-bin/cstecgi.cgi` binary, specifically in the login processing logic. The application fails to properly validate the length of user-supplied input before copying it to a fixed-size stack buffer. This allows an attacker to overwrite adjacent memory, including the instruction pointer.
## Exploitation
- **Status:** Vulnerability confirmed; PoC not included in this summary.
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** High (Attacker can read device data and configuration)
- **Integrity:** High (Attacker can modify firmware, settings, and intercept traffic)
- **Availability:** High (Attacker can crash the service or "brick" the device)
## Remediation
### Patches
- **Status:** No official patch available as of the publication date. The vendor (Totolink) did not respond to coordination attempts.
### Workarounds
- **Strict Access Control:** Disable remote management interfaces and ensure that the router’s web administration panel is not accessible from the Wide Area Network (WAN).
- **Network Segmentation:** Place the management interface on a dedicated segment or VLAN restricted to trusted administrators.
- **Device Replacement:** Given the lack of vendor response and patch availability, consider replacing the hardware with a device that receives active security support.
## Detection
- **Indicators of Compromise:** Unexpected reboots of the `cstecgi.cgi` process or the router itself; unauthorized changes to administrative credentials or configuration settings.
- **Detection Methods:** Monitor network traffic for unusually long strings or malformed payloads directed at the `/cgi-bin/cstecgi.cgi` endpoint during login attempts.
## References
- hxxps[://]cert[.]pl/en/posts/2026/06/vulnerability-in-totolink-ex1200l/
- hxxps[://]www[.]cve[.]org/CVERecord?id=CVE-2026-44089
- hxxps[://]cwe[.]mitre[.]org/data/definitions/121[.]html