Exploited· due 2022-05-03used in ransomware

CVE-2021-27065

Microsoft Exchange Server

Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.

Exploitation status

  • CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
  • It is known to have been used in ransomware campaigns.
  • US federal civilian agencies are required to remediate it by 2022-05-03. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.

Required action

Apply updates per vendor instructions.

CISA’s wording, unedited.

Scoring

CVSS
Not yet scored

Dates

Published
2021-11-03
Added to KEV
2021-11-03
Remediation due
2022-05-03
Sources
CISA KEV