What happened
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.
Affected versions
Exchange Server: See original advisory Fixed: See vendor advisory.
Why it matters
This source correlation may provide earlier visibility while structured CVE metadata is still being updated.
Detection & mitigation
- Review the original advisory and validate affected versions.
- Apply vendor-provided updates or mitigations when available.
Public PoC references
RepositoryAuthorFirst seenReference
SploitusExploit for CVE-2021-26855 and CVE-2021-26857. CVSS 9.8.Sploitus index2026-10-21T05:37:09+00:00CandidateSource timeline
Discovered through CISA Known Exploited VulnerabilitiesView source ↗
Added to CISA Known Exploited Vulnerabilities catalogView source ↗
Record history
Record created from the first normalized source observation.
Metadata and source references refreshed.