CVE-2020-0688: Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability
Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-e16c2f560820, updated 2026-11-02T23:39:54.475Z.
CISA Known Exploited Vulnerabilities
- Name
- Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability
- Vendor
- Microsoft
- Product
- Exchange Server
- Added to the catalog
- 2021-11-03
- Due date for US federal agencies
- 2022-05-03
- Weaknesses
- CWE-287
- Catalog version
- 2026.10.30
Microsoft Exchange Server Validation Key fails to properly create unique keys at install time, allowing for remote code execution.
Required action (CISA)
Apply updates per vendor instructions.
Ransomware use: CISA marks this vulnerability as known to be used in ransomware campaigns. CISA does not say which group used it.
Links in CISA's notes
Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
NVD analysis
- Status
- Analyzed
- Published
- 2020-02-11T22:15:15.900
- Last modified
- 2026-06-17T02:46:21.387
- Weaknesses
- CWE-287
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'.
| Metric | Score | Severity | Vector | Scored by |
|---|---|---|---|---|
| CVSS 3.1 | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | [email protected] (Primary) |
| CVSS 3.1 | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 2.0 | 9 | HIGH | AV:N/AC:L/Au:S/C:C/I:C/A:C | [email protected] (Primary) |
References
- http://packetstormsecurity.com/files/156592/Microsoft-Exchange-2019-15.2.221.12-Remote-Code-Execution.html (Exploit, Third Party Advisory, VDB Entry)
- http://packetstormsecurity.com/files/156620/Exchange-Control-Panel-Viewstate-Deserialization.html (Exploit, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0688 (Patch, Vendor Advisory)
- https://www.zerodayinitiative.com/advisories/ZDI-20-258/ (Third Party Advisory, VDB Entry)
- http://packetstormsecurity.com/files/156592/Microsoft-Exchange-2019-15.2.221.12-Remote-Code-Execution.html (Exploit, Third Party Advisory, VDB Entry)
- http://packetstormsecurity.com/files/156620/Exchange-Control-Panel-Viewstate-Deserialization.html (Exploit, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0688 (Patch, Vendor Advisory)
- https://www.zerodayinitiative.com/advisories/ZDI-20-258/ (Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-0688 (US Government Resource)
This product uses the NVD API but is not endorsed or certified by the NVD.
Read on 2026-11-02T23:41:43.468Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2020-0688
CVE record
- Assigner
- microsoft
- State
- PUBLISHED
- Published
- 2020-02-11T21:22:59.000Z
- Updated
- 2025-10-21T23:35:51.234Z
- Problem types
- Remote Code Execution
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'.
References
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0688
- https://www.zerodayinitiative.com/advisories/ZDI-20-258/
- http://packetstormsecurity.com/files/156592/Microsoft-Exchange-2019-15.2.221.12-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/156620/Exchange-Control-Panel-Viewstate-Deserialization.html
Read on 2026-11-03T01:02:52.377Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2020/0xxx/CVE-2020-0688.json
Detection rules (SigmaHQ)
SigmaHQ rules whose own tags name this CVE. Each rule page shows the rule as its author published it.
- CVE-2020-0688 Exploitation Attempt (status test, level high)
- CVE-2020-0688 Exploitation via Eventlog (status test, level high)
- CVE-2020-0688 Exchange Exploitation via Web Log (status test, level critical)
Defensive techniques (MITRE D3FEND)
D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.
CWE-287: Improper Authentication
- Harden: Credential Scrubbing (acts on Subroutine)
- Model: Software Inventory (acts on Software)
- Isolate: User Account Permissions (acts on User Account)
- Harden: Domain Logic Validation (acts on Subroutine)
- Restore: Unlock Account (acts on User Account)
- Harden: Trusted Library (acts on Subroutine)
- Harden: Agent Authentication (acts on User Account)
- Restore: Restore User Account Access (acts on User Account)
- Model: Asset Vulnerability Enumeration (acts on Software)
- Isolate: Application-based Process Isolation (acts on Subroutine)
- Harden: Change Default Password (acts on User Account)
- Restore: Restore Software (acts on Software)
- Harden: Variable Initialization (acts on Subroutine)
- Harden: Software Update (acts on Software)
- Model: Access Modeling (acts on User Account)
- Evict: Account Locking (acts on User Account)
D3FEND ontology version 1.6.0.
Read on 2026-11-02T23:55:44.276Z under licence d3fend-terms-of-use@f98cbc7e from https://d3fend.mitre.org/api/weakness/cwe/CWE-287.json
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/
Sources and licences
CISA
Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.
National Vulnerability Database (NIST)
This product uses the NVD API but is not endorsed or certified by the NVD.
NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)
CVE Program, The MITRE Corporation
Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
SigmaHQ
"CVE-2020-0688 Exploitation Attempt" by NVISO (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2020/Exploits/CVE-2020-0688/web_cve_2020_0688_exchange_exploit.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-LicenseSigmaHQ
"CVE-2020-0688 Exploitation via Eventlog" by Florian Roth (Nextron Systems), wagga (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2020/Exploits/CVE-2020-0688/win_vul_cve_2020_0688.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-LicenseSigmaHQ
"CVE-2020-0688 Exchange Exploitation via Web Log" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2020/Exploits/CVE-2020-0688/web_cve_2020_0688_msexchange.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-LicenseMITRE D3FEND
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT
Cite this page
Dragons Eye Ransomware Tracker, "CVE-2020-0688: Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability",
entity page, dataset version ref-e16c2f560820, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2020-0688 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-06-17T02:46:21.387.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2025-10-21T23:35:51.234Z.
Underlying source: SigmaHQ rule 7c64e577-d72e-4c3d-9d75-8de6d1f9146a, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.
Underlying source: SigmaHQ rule d6266bf5-935e-4661-b477-78772735a7cb, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.
Underlying source: SigmaHQ rule fce2c2e2-0fb5-41ab-a14c-5391e1fd70a5, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.
Underlying source: MITRE D3FEND, ontology version 1.6.0.
Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.