Exploited vulnerability · CISA KEV

Is CVE-2021-31196 exploited? Yes: in CISA KEV since 21 Aug 2024

Gociux · Microsoft Exchange Server · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2021-31196, Microsoft Exchange Server Information Disclosure Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 21 Aug 2024, 1134 days after it was published. It affects Microsoft Exchange Server. If you run it, CISA's required action is: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What it is

Microsoft Exchange Server contains an information disclosure vulnerability that allows for remote code execution.

What to do

1. Check whether you run it. Look for Exchange Server in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
2. Apply the fix. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 14 Jul 2021.
4. Get told next time. Email alerts when CISA adds a CVE for Microsoft.

Other exploited CVEs in Exchange Server

• CVE-2023-21529: Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability (13 Apr 2026)
• CVE-2024-21410: Microsoft Exchange Server Privilege Escalation Vulnerability (15 Feb 2024)
• CVE-2022-41080: Microsoft Exchange Server Privilege Escalation Vulnerability (10 Jan 2023)
• CVE-2022-41082: Microsoft Exchange Server Remote Code Execution Vulnerability (30 Sep 2022)
• CVE-2022-41040: Microsoft Exchange Server Server-Side Request Forgery Vulnerability (30 Sep 2022)
• CVE-2018-8581: Microsoft Exchange Server Privilege Escalation Vulnerability (3 Mar 2022)

References

• msrc.microsoft.com/update-guide/en-US/advisory/CVE-2021-31196
• nvd.nist.gov/vuln/detail/CVE-2021-31196

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in August 2024 · Microsoft scorecard · act-now radar.