What is CVE-2018-25221?

CVE-2018-25221 is a critical-severity vulnerability in Echatserver Easy Chat Server, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-03-28.

How severe is CVE-2018-25221?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Echatserver Easy Chat Server

CVE-2018-25221

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.

Vulnerability class: Buffer Overflow

EPSS: 0.008 (53.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Echatserver Easy_chat_server
Echatserver Echat Server — versions 3.1

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

disclosure@vulncheck.com (Exploit, exploit)
disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2018-25221?: CVE-2018-25221 is a critical-severity vulnerability in Echatserver Easy Chat Server, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-03-28.
How severe is CVE-2018-25221?: Critical severity. CVSS v3 base score is 9.8 out of 10.