CVE-2025-53786

high

Description

On April 18th 2025, Microsoft announced Exchange Server Security Changes for Hybrid Deployments and accompanying non-security Hot Fix. Microsoft made these changes in the general interest of improving the security of hybrid Exchange deployments. Following further investigation, Microsoft identified specific security implications tied to the guidance and configuration steps outlined in the April announcement. Microsoft is issuing CVE-2025-53786 to document a vulnerability that is addressed by taking the steps documented with the April 18th announcement. Microsoft strongly recommends reading the information, installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.

From the Tenable Blog

CVE-2025-53786: Frequently Asked Questions About Microsoft Exchange Server Hybrid Deployment Elevation of Privilege Vulnerability

Published: 2025-08-07

Frequently asked questions about CVE-2025-53786, an elevation of privilege vulnerability affecting Microsoft Exchange Server Hybrid Deployments.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53786

https://www.bleepingcomputer.com/news/security/cisa-warns-of-n-able-n-central-flaws-exploited-in-zero-day-attacks/

https://www.bleepingcomputer.com/news/security/canadas-house-of-commons-investigating-data-breach-after-cyberattack/

https://www.helpnetsecurity.com/2025/08/13/microsoft-fixes-badsuccessor-kerberos-vulnerability-cve-2025-53779/

https://www.infosecurity-magazine.com/news/servers-unpatched-microsoft/

https://cyberscoop.com/microsoft-patch-tuesday-august-2025/

https://www.bleepingcomputer.com/news/security/over-29-000-exchange-servers-unpatched-against-high-severity-flaw/

https://www.theregister.com/2025/08/07/microsoft_cisa_warn_yet_another/

https://www.securityweek.com/organizations-warned-of-vulnerability-in-microsoft-exchange-hybrid-deployment/

https://www.infosecurity-magazine.com/news/microsoft-exchange-vulnerability/

https://www.hipaajournal.com/warning-high-severity-flaw-microsoft-exchange-hybrid-deployments/

https://www.helpnetsecurity.com/2025/08/07/exchange-hybrid-deployment-vulnerability-cve-2025-53786/

https://www.databreachtoday.com/microsoft-warns-hybrid-exchange-deployment-flaw-a-29147

https://www.bleepingcomputer.com/news/security/cisa-orders-fed-agencies-to-patch-new-cve-2025-53786-exchange-flaw/

https://www.bleepingcomputer.com/news/microsoft/microsoft-warns-of-high-severity-flaw-in-hybrid-exchange-deployments/

https://therecord.media/microsoft-exchange-server-vulnerability-cisa-alert

https://thehackernews.com/2025/08/microsoft-discloses-exchange-server.html

https://securityaffairs.com/180923/security/cisa-microsoft-warn-of-critical-exchange-hybrid-flaw-cve-2025-53786.html

https://cyberscoop.com/cisa-microsoft-exchange-vulnerability/

https://www.tenable.com/blog/cve-2025-53786-frequently-asked-questions-about-microsoft-exchange-server-hybrid-deployment

Details

Source: Mitre, NVD

Published: 2025-08-06

Updated: 2025-08-06

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:N/AC:H/Au:M/C:C/I:C/A:C

Severity: Medium

CVSS v3

Base Score: 8

Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.00082

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability Being Monitored

Detections

Analytics