Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:L) | Local access needed |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:H) | High integrity impact |
| Availability (VA:H) | High availability impact |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
About Lizardsystems Terminal Services Manager
CVE-2018-25259 affects Lizardsystems Terminal Services Manager, a product from Lizardsystems. Before acting, confirm where Lizardsystems Terminal Services Manager runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: Terminal Services Manager 3.1 contains a stack-based buffer overflow vulnerability in the computer names field that allows local attackers to execute arbitrary code by triggering structured exception handling. Attackers can craft a malicious input file with shellcode and jump instructions that overwrite the SEH handler pointer to execute calc.exe or other payloads when imported through the add computers wizard.
The weakness class is Missing Authentication. A critical function can be used without logging in.
Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Lizardsystems Terminal Services Manager |
| Affected versions | Terminal Services Manager up to and including 3.1 |
| Published | Apr 22, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | disclosure@vulncheck.com |
How to detect it
- Inventory every instance of Lizardsystems Terminal Services Manager and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Lizardsystems Terminal Services Manager named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Lizardsystems Terminal Services Manager to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-306: Missing Authentication More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
LanSpy 2.0.1.159 contains a local buffer overflow vulnerability that allows attackers to overwrite the instruction pointer by supplying oversized input to the scan field. Attackers can craft a payload with 688 bytes of padding followed by 4 bytes of controlled data to crash the application or potentially achieve code execution.
LanSpy 2.0.1.159 contains a local buffer overflow vulnerability in the scan section that allows local attackers to execute arbitrary code by exploiting structured exception handling mechanisms. Attackers can craft malicious payloads using egghunter techniques to locate and execute shellcode, triggering code execution through SEH chain manipulation and controlled jumps.
FastGPT is an AI Agent building platform. Prior to version 4.14.9.5, the FastGPT HTTP tools testing endpoint (/api/core/app/httpTools/runTool) is exposed without any authentication. This endpoint acts as a full HTTP proxy — it accepts a user-supplied baseUrl, toolPath, HTTP method, custom headers, and body, then makes a server-side HTTP request and returns the complete response to the caller. This issue has been patched in version 4.14.9.5.
The Honeywell IQ4x building management controller, exposes its full web-based HMI without authentication in its factory-default configuration. With no user module configured, security is disabled by design and the system operates under a System Guest (level 100) context, granting read/write privileges to any party able to reach the HTTP interface. Authentication controls are only enforced after a web user is created via U.htm, which dynamically enables the user module. Because this function is accessible prior to authentication, a remote user can create a new account with administrative read/write permissions enabling the user module and imposing authentication under attacker-controlled credentials. This action can effectively lock legitimate operators out of local and web-based configuration and administration.
PolarLearn is a free and open-source learning program. In 0-PRERELEASE-16 and earlier, the group chat WebSocket at wss://polarlearn.nl/api/v1/ws can be used without logging in. An unauthenticated client can subscribe to any group chat by providing a group UUID, and can also send messages to any group. The server accepts the message and stores it in the group’s chatContent, so this is not just a visual spam issue.
Calero VeraSMART versions prior to 2022 R1 expose an unauthenticated .NET Remoting HTTP service on TCP port 8001. The service publishes default ObjectURIs (including EndeavorServer.rem and RemoteFileReceiver.rem) and permits the use of SOAP and binary formatters with TypeFilterLevel set to Full. An unauthenticated remote attacker can invoke the exposed remoting endpoints to perform arbitrary file read and write operations via the WebClient class. This allows retrieval of sensitive files such as WebRoot\\web.config, which may disclose IIS machineKey validation and decryption keys. An attacker can use these keys to generate a malicious ASP.NET ViewState payload and achieve remote code execution within the IIS application context. Additionally, supplying a UNC path can trigger outbound SMB authentication from the service account, potentially exposing NTLMv2 hashes for relay or offline cracking.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2018-25259 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications