How severe is CVE-2020-17144?

CVE-2020-17144 has a CVSS score of 8.4/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-17144?

Affected package information for CVE-2020-17144 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2020-17144?

No fixed version has been published for CVE-2020-17144 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2020-17144 actively exploited in the wild?

Yes. There are 5 known exploit references for CVE-2020-17144, including 3 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-17144?

CVE-2020-17144 has an EPSS (Exploit Prediction Scoring System) score of 92.0%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2020-17144 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2020-17144 (Microsoft Exchange Server Remote Code Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-05-03. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2020-17144?

CVE-2020-17144 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2020-17144?

CVE-2020-17144 affects microsoft exchange server (1 version, e.g. 2010). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2020-17144 published, and has it been updated?

CVE-2020-17144 was published on December 10, 2020 and was last updated on October 29, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2021-11-03 — agencies required to remediate by 2022-05-03

CVE-2020-17144

HIGH

Microsoft Exchange Remote Code Execution Vulnerability

Published

Dec 10, 2020

Updated

Oct 29, 2025

Affected

0 pkgs

Patched

None yet

Exploits

5 known

EPSS Exploitation Probability

via FIRST.org ↗

92.0%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

Microsoft Exchange Remote Code Execution Vulnerability

Affected Products

1 product · 1 configurations

Application

exchange servermicrosoft

1 version

2010

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Microsoft Exchange Remote Code Execution Vulnerability

github.comGithubDec 2020

Microsoft Exchange Remote Code Execution Vulnerability

github.comGithubDec 2020

Microsoft Exchange Remote Code Execution Vulnerability

cisa.govCISAJul 2021

Frequently Asked Questions

Microsoft Exchange Remote Code Execution Vulnerability

O3 Security · Impact-Aware SCA

Is CVE-2020-17144 in your stack?

O3 detects CVE-2020-17144 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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