# Microsoft Outlook vulnerabilities

Source: https://junglewise.ai/threats/technologies/outlook  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 11 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/technologies/outlook.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 11 vulnerabilities in Microsoft Outlook: 4 in the last 7 days and 7 in the last 90 days, 4 of them critical and 3 exploited in the wild. The most recent, CVE-2026-124194, was published on 10 November 2026. Nothing in the last four weeks, down from 1 vulnerability in the four before.

## Counts

- Last 7 days: 4
- Last 30 days: 4
- Last 90 days: 7
- All time: 11 (4 critical, 3 exploited in the wild)

## About Microsoft Outlook

Email and calendar client application by Microsoft for managing messages and scheduling.

## Latest Microsoft Outlook vulnerabilities

- [CVE-2026-124194: Microsoft Office Outlook user warning spoofing vulnerability](https://junglewise.ai/threats/cve-2026-124194-microsoft-office-outlook-missing-user-interaction-for) (critical, exploited in the wild, CVSS 6.5, published 10 Nov 2026)
- [CVE-2026-123384: Microsoft Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123384-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-2026-123380: Microsoft Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123380-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-2026-123377: Microsoft Office Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123377-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-2026-70125: Microsoft Office Outlook remote code execution](https://junglewise.ai/threats/cve-2026-70125-microsoft-office-outlook-remote-code-execution-vulnerability) (high, CVSS 8.8, published 23 Sep 2026)
- [CVE-2026-80084: Microsoft Outlook out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-80084-microsoft-outlook-out-of-bounds-read-information-disclosure) (medium, CVSS 6.5, published 8 Sep 2026)
- [CVE-2026-78509: Microsoft Outlook heap buffer overflow allows remote code execution](https://junglewise.ai/threats/cve-2026-78509-microsoft-outlook-heap-buffer-overflow-allows-remote-code) (critical, CVSS 9.8, published 8 Sep 2026)
- [CVE-2026-42893: Microsoft M365 Copilot command injection](https://junglewise.ai/threats/cve-2026-42893-microsoft-m365-copilot-command-injection) (high, CVSS 7.4, published 12 May 2026)
- [CVE-2024-21413: Microsoft Outlook Improper Input Validation Vulnerability](https://junglewise.ai/threats/cve-2024-21413-microsoft-outlook-improper-input-validation-vulnerability) (critical, exploited in the wild, CVSS 9.8, published 6 Feb 2025)
- [CVE-2023-35311: Microsoft Outlook Security Feature Bypass Vulnerability](https://junglewise.ai/threats/cve-2023-35311-microsoft-outlook-security-feature-bypass-vulnerability) (critical, exploited in the wild, CVSS 8.8, published 11 Jul 2023)
- [CVE-1999-0519: Microsoft NetBIOS and SMB null or default password on network shares](https://junglewise.ai/threats/cve-1999-0519-microsoft-netbios-and-smb-null-or-default-password-on-network) (high, CVSS 7.5, published 1 Jan 1997)

## Most severe Microsoft Outlook vulnerabilities

- [CVE-2024-21413: Microsoft Outlook Improper Input Validation Vulnerability](https://junglewise.ai/threats/cve-2024-21413-microsoft-outlook-improper-input-validation-vulnerability) (critical, exploited in the wild, CVSS 9.8, published 6 Feb 2025)
- [CVE-2023-35311: Microsoft Outlook Security Feature Bypass Vulnerability](https://junglewise.ai/threats/cve-2023-35311-microsoft-outlook-security-feature-bypass-vulnerability) (critical, exploited in the wild, CVSS 8.8, published 11 Jul 2023)
- [CVE-2026-124194: Microsoft Office Outlook user warning spoofing vulnerability](https://junglewise.ai/threats/cve-2026-124194-microsoft-office-outlook-missing-user-interaction-for) (critical, exploited in the wild, CVSS 6.5, published 10 Nov 2026)
- [CVE-2026-78509: Microsoft Outlook heap buffer overflow allows remote code execution](https://junglewise.ai/threats/cve-2026-78509-microsoft-outlook-heap-buffer-overflow-allows-remote-code) (critical, CVSS 9.8, published 8 Sep 2026)
- [CVE-2026-70125: Microsoft Office Outlook remote code execution](https://junglewise.ai/threats/cve-2026-70125-microsoft-office-outlook-remote-code-execution-vulnerability) (high, CVSS 8.8, published 23 Sep 2026)
- [CVE-2026-123384: Microsoft Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123384-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-2026-123380: Microsoft Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123380-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-2026-123377: Microsoft Office Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123377-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an) (high, CVSS 8.8, published 10 Nov 2026)
- [CVE-1999-0519: Microsoft NetBIOS and SMB null or default password on network shares](https://junglewise.ai/threats/cve-1999-0519-microsoft-netbios-and-smb-null-or-default-password-on-network) (high, CVSS 7.5, published 1 Jan 1997)
- [CVE-2026-42893: Microsoft M365 Copilot command injection](https://junglewise.ai/threats/cve-2026-42893-microsoft-m365-copilot-command-injection) (high, CVSS 7.4, published 12 May 2026)

## Vulnerabilities per week

Nothing in the last four weeks, down from 1 vulnerability in the four before.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 2 | 1 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 1 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 4 | 1 | 1 |

## Other Microsoft technologies

- [Microsoft Windows](https://junglewise.ai/threats/technologies/windows): 2,362 vulnerabilities
- [Microsoft Windows 10](https://junglewise.ai/threats/technologies/windows-10): 589 vulnerabilities
- [Microsoft Windows 11 24h2](https://junglewise.ai/threats/technologies/windows-11-24h2): 565 vulnerabilities
- [Microsoft Windows 11 25h2](https://junglewise.ai/threats/technologies/windows-11-25h2): 534 vulnerabilities
- [Microsoft Windows Server 2025](https://junglewise.ai/threats/technologies/windows-server-2025): 534 vulnerabilities
- [Microsoft Windows Server 2022](https://junglewise.ai/threats/technologies/windows-server-2022): 528 vulnerabilities
- [Microsoft Windows Server 2019](https://junglewise.ai/threats/technologies/windows-server-2019): 521 vulnerabilities
- [Microsoft Windows Server 2012](https://junglewise.ai/threats/technologies/windows-server-2012): 517 vulnerabilities
- [Microsoft Windows 11](https://junglewise.ai/threats/technologies/windows-11): 494 vulnerabilities
- [Microsoft Windows Server 2016](https://junglewise.ai/threats/technologies/windows-server-2016): 476 vulnerabilities
- [Microsoft Windows 10 1809](https://junglewise.ai/threats/technologies/windows-10-1809): 380 vulnerabilities
- [Microsoft Windows 10 21h2](https://junglewise.ai/threats/technologies/windows-10-21h2): 373 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Microsoft Outlook vulnerabilities", https://junglewise.ai/threats/technologies/outlook, 11 November 2026.