What is the CVSS score of CVE-2020-0688?

CVE-2020-0688 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 94.4%.

Which versions of Microsoft Exchange are affected by CVE-2020-0688?

CVE-2020-0688 presents significant security risk, a improper authentication vulnerability rated CVSS 8.8.. A patch is available.

Is there a public PoC exploit available for CVE-2020-0688?

Yes, a public proof-of-concept exploit is available for CVE-2020-0688. Prioritise patching immediately. EPSS: 94.4%.

How to fix or mitigate CVE-2020-0688?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Audit authentication configurations and rotate any potentially compromised credentials.

Microsoft Exchange CVE-2020-0688

HIGH

Improper Authentication (CWE-287)

2020-02-11 secure@microsoft.com

8.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 26, 2026 - 11:19 vuln.today

Added to CISA KEV

Oct 29, 2025 - 14:27 cisa

CISA KEV

PoC Detected

Oct 29, 2025 - 14:27 vuln.today

Public exploit code

Patch released

Oct 29, 2025 - 14:27 nvd

Patch available

CVE Published

Feb 11, 2020 - 22:15 nvd

HIGH 8.8

DescriptionCVE.org

A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, aka 'Microsoft Exchange Memory Corruption Vulnerability'.

AnalysisAI

Microsoft Exchange Server contains a remote code execution vulnerability caused by static cryptographic keys used in the Exchange Control Panel, allowing authenticated attackers to execute code as SYSTEM.

Technical ContextAI

The CWE-287 authentication flaw stems from Exchange using a static validationKey and decryptionKey in web.config for ViewState MAC validation. An authenticated attacker (any mailbox user) can craft a serialized ViewState payload, sign it with the known static key, and send it to ECP for deserialization and code execution as SYSTEM.