Is there a public PoC exploit available for EUVD-2018-21727?

Yes, a public proof-of-concept exploit is available for EUVD-2018-21727. Prioritise patching immediately. EPSS: 0.0%.

Networkactiv Web Server EUVD-2018-21727

Q: What is the CVSS score of EUVD-2018-21727?

EUVD-2018-21727 has a CVSS 4.0 base score of 6.9 (Medium). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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. EPSS exploitation probability: 0.0%.

| CVE-2018-25235 MEDIUM

Out-of-bounds Write (CWE-787)

2026-03-30 VulnCheck

GHSA-x4g8-cm9x-f937

Memory Corruption Buffer Overflow Denial Of Service Networkactiv Web Server

6.9

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

6.9 MEDIUM

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

PoC Detected

Apr 08, 2026 - 16:35 vuln.today

Public exploit code

EUVD ID Assigned

Mar 30, 2026 - 11:30 euvd

EUVD-2018-21727

CVE Published

Mar 30, 2026 - 11:02 nvd

MEDIUM 6.9

DescriptionCVE.org

NetworkActiv Web Server 4.0 contains a buffer overflow vulnerability in the username field of the Security options that allows local attackers to crash the application by supplying an excessively long string. Attackers can trigger a denial of service by entering a crafted username value exceeding the expected buffer size through the Set username interface.

AnalysisAI

NetworkActiv Web Server 4.0 contains a buffer overflow vulnerability in the username field of the Security options that allows local attackers to crash the application by supplying an excessively. Rated medium severity (CVSS 6.9), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. NetworkActiv Web Server 4.0 contains a buffer overflow vulnerability in the username field of the Security options that allows local attackers to crash the application by supplying an excessively long string. Attackers can trigger a denial of service by entering a crafted username value exceeding the expected buffer size through the Set username interface. Affected products include: Networkactiv Networkactiv Web Server.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).