Quick answers
- Is CVE-2026-123379 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-123379 being exploited in the wild.
- How severe is CVE-2026-123379?
- High severity, with a CVSS score of 7.5, published 10 November 2026.
- Which products and versions are affected?
- Microsoft Office Outlook.
- Is there a fix for CVE-2026-123379?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-123379 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-123379?
- Check whether you run Microsoft Office Outlook. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A heap-based buffer overflow exists in Microsoft Office Outlook that can be exploited via network-supplied input (e.g., malicious email or calendar data). An attacker can trigger the overflow by sending specially crafted content, achieving remote code execution with the privileges of the user running Outlook. No authentication is required; the attack occurs during normal email/calendar processing.
Affected products
- Microsoft Office Outlook
Timeline
- 2026-11-10: disclosed