Quick answers
- Is CVE-2026-77503 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77503 being exploited in the wild.
- How severe is CVE-2026-77503?
- High severity, with a CVSS score of 8.4, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Windows NTFS <UNKNOWN>.
- Is there a fix for CVE-2026-77503?
- 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-2026-77503 attacked?
- It is attacked with local access.
- Am I affected by CVE-2026-77503?
- Check whether you run Microsoft Windows NTFS 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
An out-of-bounds read vulnerability exists in the Windows NTFS driver, allowing an attacker to read memory beyond allocated boundaries. The vulnerability is exploitable locally and can be leveraged to achieve privilege escalation. The attack does not require user interaction or prior elevated privileges, making it a viable local privilege escalation vector. A patch has been released by Microsoft to address this issue.
Affected products
- Microsoft Windows NTFS <UNKNOWN>
Timeline
- 2026-09-08: disclosed
- 2026-09-08: advisory