What is CVE-2018-16793?

CVE-2018-16793 is a high-severity vulnerability in Microsoft Exchange Server, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2018-09-21.

How severe is CVE-2018-16793?

High severity. CVSS v3 base score is 8.6 out of 10.

SSRF in Microsoft Exchange Server

CVE-2018-16793

Rollup 18 for Microsoft Exchange Server 2010 SP3 and previous versions has an SSRF vulnerability via the username parameter in /owa/auth/logon.aspx in the OWA (Outlook Web Access) login page.

Vulnerability class: SSRF (Server-Side Request Forgery)

Published 2018-09-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.113 (95.9th percentile), scored 2026-10-03.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 95.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.113 · newest: 0.113 · change: 0.000

Affected products

Microsoft Exchange Server — versions 2010

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

packetstormsecurity.com/files/149411/Rollup-18-For-Microsoft-Exchange-Server-20… (Exploit, VDB Entry, Third Party Advisory)
seclists.org/fulldisclosure/2018/Sep/20 (mailing-list, Exploit, Mailing List, Third Party Advisory)
www.securityfocus.com/bid/105386 (VDB Entry, Third Party Advisory, vdb-entry)
seclists.org/bugtraq/2018/Sep/38 (mailing-list, Exploit, Mailing List, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2018-16793?: CVE-2018-16793 is a high-severity vulnerability in Microsoft Exchange Server, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2018-09-21.
How severe is CVE-2018-16793?: High severity. CVSS v3 base score is 8.6 out of 10.