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CVE-2020-16969

HIGHCVSS 7.1/10EPSS 2.53%

Last modified

CVE-2020-16969 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. <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. EPSS estimates a 2.53% chance of exploitation in the next 30 days.

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>

Metrics

CVSS 3.1
7.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

EPSS Probability
2.53%

82.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
MicrosoftExchange Server2013Cumulative Update 23
MicrosoftExchange Server2016Cumulative Update 17
MicrosoftExchange Server2019Cumulative Update 6

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-16969?
<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>
How severe is CVE-2020-16969?
CVE-2020-16969 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 2.53% probability of exploitation in the next 30 days.
How do I fix CVE-2020-16969?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-16969?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST