Quick answers
- Is CVE-2026-45455 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-45455 being exploited in the wild.
- How severe is CVE-2026-45455?
- Low severity, with a CVSS score of 3.3, published 9 June 2026.
- Which products and versions are affected?
- Microsoft Excel.
- Is there a fix for CVE-2026-45455?
- 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-2026-45455 attacked?
- It is attacked with local access, in a network appliance.
- Am I affected by CVE-2026-45455?
- Check whether you run Microsoft Excel. 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
An out-of-bounds read vulnerability (CWE-125) exists in Microsoft Office Excel. The flaw is triggered when the application reads data past the end of the intended buffer while processing a malformed file. An attacker can exploit this by convincing a user to open a malicious Excel document. Successful exploitation allows the attacker to disclose sensitive information from the process memory, though it does not inherently allow for code execution or data modification. The CVSS vector (AV:L/AC:L/PR:N/UI:R) indicates a local attack vector requiring user interaction.
Affected products
- Microsoft Excel
Timeline
- 2026-06-09: disclosed: Initial publication of the CVE record.
- 2026-06-09: advisory: Microsoft released the security advisory and update guide.