# Microsoft Exchange Server Information Disclosure · pwn.watch

> Microsoft Exchange Server contains an information disclosure vulnerability that allows for remote code execution. Added to the CISA KEV catalog on 2024-08-21. CVE-2021-31196 was assigned before 2024; the KEV listing came in 2024.

Page: https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196 · generated 2026-10-22T22:41:49.181Z

## Status
- Severity: high · status: closed · patch: patched
- Product: Microsoft Exchange Server
- Started: 2024-08-21 · closed: 2024-08-21
- CVEs: CVE-2021-31196
- Affected: See vendor advisory (versions are not listed in the KEV record)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196/feed.xml
- JSON Feed: https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196.json
- This file: https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196/llms.txt

## Updates (newest first)
- 2024-08-21: CISA added CVE-2021-31196 to the KEV catalog (federal deadline 2024-09-11) (https://www.cisa.gov/known-exploited-vulnerabilities-catalog)

## Fix brief
# Security brief: Microsoft Exchange Server Information Disclosure

Source: https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196 · status: closed (closed Aug 21, 2024) · severity: high · updated Aug 21, 2024

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
Microsoft Exchange Server contains an information disclosure vulnerability that allows for remote code execution. Added to the CISA KEV catalog on 2024-08-21. CVE-2021-31196 was assigned before 2024; the KEV listing came in 2024.

Severity detail: CVSS 7.2 (v3.1, CNA), actively exploited (CISA KEV)

- Product: Microsoft Exchange Server
- CVE / advisory ids: CVE-2021-31196

## Affected versions
- See vendor advisory (versions are not listed in the KEV record)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Aug 21, 2024: CISA added CVE-2021-31196 to the KEV catalog (federal deadline 2024-09-11)

## Advisories
- [Microsoft advisory: CVE-2021-31196](https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2021-31196) (Microsoft)
- [NVD: CVE-2021-31196](https://nvd.nist.gov/vuln/detail/CVE-2021-31196) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from the CISA KEV JSON feed (catalogVersion 2026.10.21); CVSS from the CVE record (cveawg.mitre.org). startedAt is the CVE publication date when it fell in 2024 before the KEV listing, else the KEV dateAdded; exploitation may have begun earlier. closedAt is the KEV listing date (a fix or mitigation was available then unless noted).

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Machine-readable: https://pwn.watch/i/microsoft-exchange-server-cve-2021-31196.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.