CVE-2020-16969
Microsoft Exchange Information Disclosure Vulnerability
Published Oct 16, 2020
CVSS 3.1 · 7.1 High
EPSS 2.7%
KEV · Not listed
Description
<p>An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.</p>
<p>To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.</p>
<p>The security update corrects the way that Exchange handles these token validations.</p>
<p>To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.</p>
<p>The security update corrects the way that Exchange handles these token validations.</p>
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
No data
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OpenCVE enrichment
No data
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 6 | affected |
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| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 17 | affected |
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| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 7 | affected |
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| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 18 | affected |
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| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 23 | affected |
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Configuration 1 [-]
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No data.
No data available yet.
Remediation
Tracking
Advisories
| Source | ID | Title |
|---|---|---|
 EUVD |
EUVD-2020-8927 | <p>An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.</p> <p>To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.</p> <p>The security update corrects the way that Exchange handles these token validations.</p> |
Metrics
No CVSS v4.0
Attack Vector Network
Attack Complexity Low
Privileges Required None
Scope Changed
Confidentiality Impact Low
Integrity Impact Low
Availability Impact Low
User Interaction Required
No CVSS v3.0
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact Partial
Integrity Impact None
Availability Impact None
This CVE is not in the KEV list.
Exploit prediction score: 2.7% (2.730% probability within 30 days)
Key SSVC decision points have not yet been added.
References
History
Feb 23, 2026 6:15 PM
Description updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | <p>An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.</p> <p>To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.</p> <p>The security update corrects the way that Exchange handles these token validations.</p> | <p>An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.</p> <p>To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.</p> <p>The security update corrects the way that Exchange handles these token validations.</p> |
Jul 16, 2025 1:45 PM
Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
epss
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epss
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Subscriptions
Weaknesses
