CVE-2026-20963: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-03-21T13:39:25.555Z. This file is automatically regenerated every 30 minutes by the CVE AI enrichment job using web sources (NVD, MITRE, CISA KEV, GitHub).

Executive Technical Summary

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

• Context preserved from previous revision: Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network. 1. Use only isolated environments and assets you own or are explicitly authorized to test.

Technical Details

• CVE: CVE-2026-20963
• KEV date added: 2026-03-18
• KEV due date: 2026-03-21
• NVD published: 2026-01-13
• NVD modified: 2026-03-19
• MITRE modified: 2026-03-19
• CVSS base score: 8.8
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• CVSS exploitability score: 2.8
• CVSS impact score: 5.9
• Attack vector: Network
• Attack complexity: Low
• Privileges required: Low
• User interaction: None
• Scope: Unchanged
• Confidentiality impact: High
• Integrity impact: High
• Availability impact: High

Versions and Products Impacted

• microsoft / sharepoint server (versions: < 16.0.19127.20442)
• microsoft / sharepoint server (versions: 2016)
• microsoft / sharepoint server (versions: 2019)
• Microsoft / Microsoft SharePoint Enterprise Server 2016 (versions: 16.0.0)
• Microsoft / Microsoft SharePoint Server 2019 (versions: 16.0.0)
• Microsoft / Microsoft SharePoint Server Subscription Edition (versions: 16.0.0)

Weakness Classification

• CWE-502

Repositories for Lab Validation (Public Examples)

• Ostorlab/KEV | stars: 607 | updated: 2026-03-16 | https://github.com/Ostorlab/KEV
  Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

People and Organizations Mentioned

• microsoft
• SharePoint
• Ostorlab

Practical Defensive Validation (Authorized Only)

1. Use only isolated environments and systems you own or are explicitly authorized to test.
2. Snapshot infrastructure before validation and preserve baseline logs (EDR, SIEM, OS, app).
3. Inventory microsoft / sharepoint server (versions: < 16.0.19127.20442) assets and confirm exact vulnerable versions with automated checks.
4. Patch in staged environments and validate closure with scanners + service health checks.
5. Map detections to MITRE ATT&CK tactics relevant to your environment and tune alert quality.

References

• NVD record: https://nvd.nist.gov/vuln/detail/CVE-2026-20963
• MITRE CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20963
• CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• CISA KEV JSON feed: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
• KEV notes: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963 ; https://nvd.nist.gov/vuln/detail/CVE-2026-20963
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20963
• Repository example: https://github.com/Ostorlab/KEV

This content is for defensive security training and authorized validation only.