CVE-2026-21513: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-03-23T17:27:41.393Z. 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

Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.

• Context preserved from previous revision: Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network. Notes: Cerberus-CVE Assessment Situation

Technical Details

• CVE: CVE-2026-21513
• KEV date added: 2026-02-10
• KEV due date: 2026-03-03
• NVD published: 2026-02-10
• NVD modified: 2026-02-11
• MITRE modified: 2026-03-16
• CVSS base score: 8.8
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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: None
• User interaction: Required
• Scope: Unchanged
• Confidentiality impact: High
• Integrity impact: High
• Availability impact: High

Versions and Products Impacted

• microsoft / windows 10 1607 (versions: < 10.0.14393.8868)
• microsoft / windows 10 1809 (versions: < 10.0.17763.8389)
• microsoft / windows 10 21h2 (versions: < 10.0.19044.6937)
• microsoft / windows 10 22h2 (versions: < 10.0.19045.6937)
• microsoft / windows 11 23h2 (versions: < 10.0.22631.6649)
• microsoft / windows 11 24h2 (versions: < 10.0.26100.7781)
• microsoft / windows 11 25h2 (versions: < 10.0.26200.7781)
• microsoft / windows server 2012
• microsoft / windows server 2012 (versions: r2)
• microsoft / windows server 2016 (versions: < 10.0.14393.8868)
• microsoft / windows server 2019 (versions: < 10.0.17763.8389)
• microsoft / windows server 2022 (versions: < 10.0.20348.4711)
• microsoft / windows server 2022 23h2 (versions: < 10.0.25398.2149)
• microsoft / windows server 2025 (versions: < 10.0.26100.32313)
• Microsoft / Windows 10 Version 1607 (versions: 10.0.14393.0)
• Microsoft / Windows 10 Version 1809 (versions: 10.0.17763.0)
• Microsoft / Windows 10 Version 21H2 (versions: 10.0.19044.0)
• Microsoft / Windows 10 Version 22H2 (versions: 10.0.19045.0)
• Microsoft / Windows 11 version 22H3 (versions: 10.0.22631.0)
• Microsoft / Windows 11 Version 23H2 (versions: 10.0.22631.0)

Weakness Classification

• CWE-693

Repositories for Lab Validation (Public Examples)

• ekomsSavior/Cerberus | stars: 15 | updated: 2026-03-13 | https://github.com/ekomsSavior/Cerberus
  Notes: Cerberus-CVE Assessment Situation
• Kwaai-AI-Lab/OpenAI-Petal | stars: 3 | updated: 2026-02-24 | https://github.com/Kwaai-AI-Lab/OpenAI-Petal
  Notes: OpenAI api compliant api server for petals
• greenido/CISA-alerts-bot | stars: 0 | updated: 2026-02-13 | https://github.com/greenido/CISA-alerts-bot
  Notes: A stateless GitHub Action that monitors Cybersecurity Alerts and sends structured alerts to Slack / Telegram

People and Organizations Mentioned

• microsoft
• Windows
• ekomsSavior
• Kwaai-AI-Lab
• greenido

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 / windows 10 1607 (versions: < 10.0.14393.8868) 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-2026-21513
• MITRE CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21513
• 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/advisory/CVE-2026-21513 ; https://nvd.nist.gov/vuln/detail/CVE-2026-21513
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21513
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21513
• Repository example: https://github.com/ekomsSavior/Cerberus
• Repository example: https://github.com/Kwaai-AI-Lab/OpenAI-Petal
• Repository example: https://github.com/greenido/CISA-alerts-bot

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