Is CVE-2017-8621 being actively exploited?

CVE-2017-8621 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2017-8621?

CVE-2017-8621 has a CVSS 3.0 base score of 6.1 (MEDIUM).

CVE-2017-8621

MEDIUM · CVSS 6.1EPSS 3.2%EU EUVD

Microsoft Exchange Server 2010 SP3, Exchange Server 2013 SP3, Exchange Server 2013 CU16, and Exchange Server 2016 CU5 allows an open redirect vulnerability that could lead to spoofing, aka "Microsoft Exchange Open Redirect Vulnerability".

Key facts

CVSS score: 6.1 (v3.0)
Severity: MEDIUM
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-601
EPSS score: 3.2% (88th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2017-17570)
Published: July 11, 2017
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2017-17570 in the EU Vulnerability Database. Last updated in EUVD on September 16, 2024.

View on the EU Vulnerability Database

Affected products

microsoft / exchange server
microsoft / exchange server
microsoft / exchange server
microsoft / exchange server

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

Microsoft Exchange Server 2010 SP1 Enterprise (English) 64-bit - Microsoft Corporation - Common Criteria Certificate Number: 2011/72 - archived

References

http://www.securityfocus.com/bid/99533(Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id/1038852(Third Party Advisory, VDB Entry)
https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2017-8621(Patch, Vendor Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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