VulnerabilityModified

CVE-2021-26854

Microsoft Exchange Server Remote Code Execution Vulnerability

MEDIUM 6.6EPSS 24.7%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 24.7%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

CVSS 3.1: 6.6 MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS: 24.74% probability · 98th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Affected: microsoft/exchange server
Source: secure@microsoft.com

EPSS trend

EPSS moved from 24.7% on 21 September 2026 to 24.7% on 3 November 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26854
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26854Patch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.