CVE Intel / CVE-2021-26855
CVE-2021-26855
exchange server · microsoft
What it is
Microsoft Exchange Server Remote Code Execution Vulnerability
Live exploitation on the huntback network (30 days)
12
attempts captured
10
distinct source IPs
2026-09-23
last seen
huntback carries a network signature for this CVE. Exploitation attempts are detected on the decoy fleet in real time.
How huntback helps
Deploy a decoy that emulates exchange server and you will see every attempt at this CVE the moment it lands, with the full payload, the attacker's infrastructure, and any stage-2 loader. Then huntback can scan the attacker back.
CVSSn/a Critical
EPSS1.00 (99% pct)
In CISA KEVyes
Publishedn/a
Network detectableyes, signatured