How severe is CVE-2019-0817?

CVE-2019-0817 has a CVSS 3.x base score of 5.4, 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-2019-0817 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-0817?

CVE-2019-0817 primarily affects Microsoft Exchange Server. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-0817?

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

When was CVE-2019-0817 published?

CVE-2019-0817 was published on 2019-04-09 and last updated on 2026-06-17.

CVE-2019-0817

CVE-2019-0817 is a medium-severity vulnerability in Microsoft Exchange Server with a CVSS 3.x base score of 5.4. 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-19.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 5.8
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-19
Affected product: Microsoft Exchange Server
Published: 2019-04-09
Last modified: 2026-06-17

Description

A spoofing vulnerability exists in Microsoft Exchange Server when Outlook Web Access (OWA) fails to properly handle web requests, aka 'Microsoft Exchange Spoofing Vulnerability'. This CVE ID is unique from CVE-2019-0858.

Frequently asked questions

What is CVE-2019-0817?: A spoofing vulnerability exists in Microsoft Exchange Server when Outlook Web Access (OWA) fails to properly handle web requests, aka 'Microsoft Exchange Spoofing Vulnerability'. This CVE ID is unique from CVE-2019-0858.
How severe is CVE-2019-0817?: CVE-2019-0817 has a CVSS 3.x base score of 5.4, 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-2019-0817 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-0817?: CVE-2019-0817 primarily affects Microsoft Exchange Server. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-0817?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-0817 published?: CVE-2019-0817 was published on 2019-04-09 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0817

Affected products (6)

cpe:2.3:a:microsoft:exchange_server:2010:sp3:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_22:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_11:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_12:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_1:*:*:*:*:*:*

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