⚠ Known Exploited Vulnerability (KEV) Tracker

Description

Microsoft Exchange Server contains an unspecified vulnerability that allows for authenticated remote code execution. Dubbed "ProxyNotShell," this vulnerability is chainable with CVE-2022-41040 which allows for the remote code execution.

Lifecycle Timeline

• 2022-09-28
  Public exploit code

  Metasploit — Microsoft Exchange ProxyNotShell RCE

  Metasploit →
• 2022-09-30
  Added to CISA KEV 2 days later

  Listed as known exploited, which starts the federal remediation clock.

  CISA KEV →
• 2022-09-30
  Vendor fix published

  Microsoft shipped a fix for Microsoft Exchange Server.

  MSRC →
• 2022-10-03
  CVE published 3 days later

  Entered the public CVE record.

  CVE.org →
• 2022-10-08
  EPSS flags exploitation risk 5 days later

  Entered EPSS already at 25.1%. Dated to the sampled week.

  FIRST EPSS →
• 2022-10-21
  Federal remediation due 13 days later

  Deadline for federal civilian agencies under BOD 22-01 — now passed.

  CISA KEV
• 2025-06-04
  First national advisory 2.6 years later

  FBI — #StopRansomware: Play Ransomware

  CyberzSOC advisory index →

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 219 points from 2022-10-08, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 100.0% on 2026-07-11.

Published Applicability

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

Articles from monitored vendor research blogs and security news feeds that specifically mention this CVE. Coverage begins when feed monitoring started; earlier articles are not indexed.

Detection & Exploitation

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

Microsoft Exchange Server Remote Code Execution Vulnerability

The vendor's own judgement about their own code, shown alongside CISA's rather than merged into it. The exploitability index is a forward-looking prediction, distinct from a CVSS severity or CISA's SSVC decision, and vendors often report observed exploitation before a CVE reaches the KEV catalog. Vendor advisory →

CISA Assessment (Vulnrichment / SSVC)

D3FEND Countermeasures

Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-502) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.

KEV Catalog Status

Listed By

Referenced in Advisories

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References

CVE.org record → NVD entry → CISA KEV catalog → Microsoft MSRC advisory → FortiGuard Labs → Rapid7 AttackerKB →