What is CVE-2017-9544?

CVE-2017-9544 is a critical-severity vulnerability in Echatserver Easy Chat Server, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2017-06-12.

How severe is CVE-2017-9544?

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

Is CVE-2017-9544 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Echatserver Easy Chat Server

CVE-2017-9544

There is a remote stack-based buffer overflow (SEH) in register.ghp in EFS Software Easy Chat Server versions 2.0 to 3.1. By sending an overly long username string to registresult.htm for registering the user, an attacker may be able to execute arbitrary code.

Vulnerability class: Buffer Overflow

Published 2017-06-12 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.241 (97.8th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.241 · newest: 0.241 · change: 0.000

Affected products

Echatserver Easy Chat Server

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

Public proof-of-concept exploits

References

www.exploit-db.com/exploits/42155/ (Exploit, VDB Entry, Third Party Advisory, exploit)

Frequently asked questions

What is CVE-2017-9544?: CVE-2017-9544 is a critical-severity vulnerability in Echatserver Easy Chat Server, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2017-06-12.
How severe is CVE-2017-9544?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2017-9544 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.