CVE-2018-25221

CriticalPublic PoC

Published: 28 March 2026

Published

28 March 2026

Modified

02 April 2026

KEV Added

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Patch

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CVSS Score v4 9.3 CVSS:4.0/AV:N/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

EPSS Score 0.0082 52.5th percentile

Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2018-25221 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Echatserver Easy Chat Server. Its CVSS base score is 9.3 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 47.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Deeper analysis

CVE-2018-25221 is a buffer overflow vulnerability (CWE-787) in EChat Server 3.1, specifically affecting the chat.ghp endpoint. The issue arises from processing an oversized username parameter, which can trigger a buffer overflow. Published on 2026-03-28, it carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity due to its potential for high-impact remote exploitation.

Remote, unauthenticated attackers can exploit this vulnerability by sending a GET request to the chat.ghp endpoint with a malicious username parameter containing shellcode and ROP gadgets. Successful exploitation leads to arbitrary code execution in the context of the affected application.

Advisories and related resources include a Vulncheck advisory detailing the buffer overflow via the chat.ghp username parameter and a public exploit published on Exploit-DB at https://www.exploit-db.com/exploits/44155. No specific patch or mitigation details are outlined in the provided information.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2018-21700

Vulnerability details

EChat Server 3.1 contains a buffer overflow vulnerability in the chat.ghp endpoint that allows remote attackers to execute arbitrary code by supplying an oversized username parameter. Attackers can send a GET request to chat.ghp with a malicious username value containing…

shellcode and ROP gadgets to achieve code execution in the application context.

CWE(s): CWE-787

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

CVE-2018-25221 is a buffer overflow in a public-facing chat server endpoint (chat.ghp) allowing unauthenticated remote code execution via crafted GET request, directly mapping to Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0