How severe is CVE-2017-8621?

CVE-2017-8621 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2017-8621 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-8621?

CVE-2017-8621 primarily affects Microsoft Exchange Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-8621?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2017-8621 published?

CVE-2017-8621 was published on 2017-07-11 and last updated on 2026-06-17.

CVE-2017-8621

CVE-2017-8621 is a medium-severity vulnerability in Microsoft Exchange Server with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 5.8
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Microsoft Exchange Server
Published: 2017-07-11
Last modified: 2026-06-17

Description

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".

Frequently asked questions

What is CVE-2017-8621?: 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".
How severe is CVE-2017-8621?: CVE-2017-8621 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2017-8621 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-8621?: CVE-2017-8621 primarily affects Microsoft Exchange Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-8621?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-8621 published?: CVE-2017-8621 was published on 2017-07-11 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:microsoft:exchange_server:2010:sp3:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_16:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2013:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_5:*:*:*:*:*:*

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