Quick answers
- Is CVE-2026-102858 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-102858 being exploited in the wild.
- How severe is CVE-2026-102858?
- High severity, with a CVSS score of 8.8, published 13 October 2026.
- Which products and versions are affected?
- Microsoft Office OneNote.
- Is there a fix for CVE-2026-102858?
- 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-2026-102858 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-102858?
- Check whether you run Microsoft 365, Microsoft Office 2021, Microsoft Office 2024 or one of the others listed. 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 vulnerability exists in Microsoft Office OneNote that can be triggered via network vectors, allowing remote code execution without prior authentication. The vulnerability results from improper bounds checking when processing malformed input, enabling an attacker to overwrite heap memory and redirect execution flow. No patch information is provided in the available advisory references.
Affected products
- Microsoft Office OneNote
Timeline
- 2026-10-13: disclosed