CVE-2021-42305: Microsoft Exchange Server Spoofing Vulnerability

Published Nov 9, 2021
·
Updated

Microsoft Exchange Server Spoofing Vulnerability

Affected Software

10 affected componentsFixes available
Microsoft Exchange Server=2013-cumulative_update_23
Microsoft Exchange Server=2016-cumulative_update_21
Microsoft Exchange Server=2016-cumulative_update_22
Microsoft Exchange Server=2019-cumulative_update_10
Microsoft Exchange Server=2019-cumulative_update_11
Microsoft Exchange Server 2016=21
15.01.2308.020
Microsoft Exchange Server 2019=10
15.02.0792.019
Microsoft Exchange Server 2016=22
15.01.2375.017
Microsoft Exchange Server 2019=11
15.02.0986.014
Microsoft Exchange Server 2013=23
15.00.1497.026

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.01.2308.020Patch KB5007409
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.02.0792.019Patch KB5007409
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.02.0986.014Patch KB5007409
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.01.2375.017Patch KB5007409
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 15.00.1497.026Patch KB5007409

Event History

Nov 9, 2021
CVE Published
via Microsoft·08:00 AM
Data Sourced
via Microsoft·08:00 AM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·08:00 AM
Affected Software
Updated
via Microsoft·08:00 AM
Description
Nov 10, 2021
CVE Published
via MITRE·12:47 AM
Data Sourced
via MITRE·12:47 AM
DescriptionSeverity
Data Sourced
via NVD·01:19 AM
RemedyDescriptionSeverityAffected Software

Frequently Asked Questions

1

What is CVE-2021-42305?

CVE-2021-42305 is a Spoofing Vulnerability in Microsoft Exchange Server.

2

What versions of Microsoft Exchange Server are affected by CVE-2021-42305?

CVE-2021-42305 affects Microsoft Exchange Server 2013 Cumulative Update 23, 2016 Cumulative Update 21 and 22, and 2019 Cumulative Update 10 and 11.

3

What is the severity of CVE-2021-42305?

CVE-2021-42305 has a severity rating of 6.5 (Medium).

4

How can I fix CVE-2021-42305?

To fix CVE-2021-42305, it is recommended to apply the necessary security updates provided by Microsoft.

5

Where can I find more information about CVE-2021-42305?

You can find more information about CVE-2021-42305 on the Microsoft Security Guidance Advisory page: [https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42305](https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42305).

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203