CVE-2021-27065KEV ยท OVERDUECWE-22path-traversal

Microsoft Exchange Server Remote Code Execution Vulnerability

High ยท published March 3, 2021

Patch now

Confirmed exploited, and the score agrees

CVSS calls it high at 7.8. It is confirmed in active exploitation. It sits in the 100.0th percentile for exploit probability.

1635
days past CISA
deadline
CVSS v3.1
7.8
EPSS
100%
Percentile
100.0
In the wild
Confirmed
What it is

๐Ÿšจ A sneaky remote code execution vulnerability in Microsoft Exchange Server can let attackers run scripts with minimal effort โ€” just like a cat burglar slipping through an unlocked window! โšก Think of this vulnerability as a poorly secured backdoor in a hotel โ€” if it's left unguarded, anyone can sneak in and access all the rooms. ๐Ÿ” If exploited, an attacker can take full control of the server, potentially leading to data breaches, unauthorized access to emails, and even a complete system takeover. This could be absolutely devastating for your organization's security!

Put simply

Think of this vulnerability as a poorly secured backdoor in a hotel โ€” if it's left unguarded, anyone can sneak in and access all the rooms. ๐Ÿ” CVE-2021-27065 is a remote code execution vulnerability in Microsoft Exchange Server that allows an unauthenticated attacker to execute arbitrary code through a specially crafted request.

What to do

If exploited, an attacker can take full control of the server, potentially leading to data breaches, unauthorized access to emails, and even a complete system takeover. This could be absolutely devastating for your organization's security! Immediately patch your Exchange Server to the latest version to close this vulnerability. Ensure that all security updates are applied, and consider reviewing your server configurations for any additional security measures. You've got this! Stay vigilant, apply those patches, and you'll keep your systems secure. ๐Ÿ›ก๏ธ

The record
Technical detail
CVSS v3.1
7.8 ยท HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.99876 ยท 100.0th percentile
Weakness
CWE-22 ยท Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2021-03-03T05:15Z
KEV added
2021-11-03 ยท due 2022-05-03
Affected products (24)
ProductVersionsFixed in
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
microsoft/exchange_serverall versionsโ€”
References (5)
EPSS history
Timeline
  • 03 NOV 00:00Z
    Added to CISA KEV โ€” remediate by May 3
    kev
  • 02 MAR 23:55Z
    Microsoft Exchange Server Remote Code Execution Vulnerability
    cvelistv5