Quick answers
- Is CVE-2026-81396 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-81396 being exploited in the wild.
- How severe is CVE-2026-81396?
- High severity, with a CVSS score of 7.8, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Excel <UNKNOWN>.
- Is there a fix for CVE-2026-81396?
- 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-2026-81396 attacked?
- It is attacked with local access, in a web application.
- Am I affected by CVE-2026-81396?
- Check whether you run Microsoft Excel at an affected version. 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 stack-based buffer overflow exists in Microsoft Excel's file parsing logic, allowing an attacker to write beyond the boundaries of a stack-allocated buffer. The vulnerability requires local code execution context and user interaction (opening a malicious .xls or related file format). An attacker can exploit this by crafting a specially formatted Excel document that triggers the overflow when processed, achieving arbitrary code execution in the context of the user running Excel. A patch is expected to be available through Microsoft Security Updates.
Affected products
- Microsoft Excel <UNKNOWN>
Timeline
- 2026-09-08: disclosed