Quick answers
- Is CVE-2026-40410 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-40410 being exploited in the wild.
- How severe is CVE-2026-40410?
- High severity, with a CVSS score of 7, published 12 May 2026.
- Which products and versions are affected?
- Microsoft Windows SMB Client.
- Is there a fix for CVE-2026-40410?
- 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-2026-40410 attacked?
- It is attacked with local access, in an operating system.
- Am I affected by CVE-2026-40410?
- Check whether you run Microsoft Windows SMB Client. 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 use-after-free vulnerability (CWE-416) exists within the Microsoft Windows SMB Client driver. The flaw is triggered when the system incorrectly manages memory objects during SMB communication, allowing an attacker to reuse a memory pointer after it has been freed. To exploit this, an attacker must first have local access to the system with low-level privileges. Successful exploitation allows the attacker to execute arbitrary code with elevated system privileges. Microsoft has assigned a CVSS score of 7.0, noting high complexity for successful exploitation.
Affected products
- Microsoft Windows SMB Client
Timeline
- 2026-05-12: disclosed
- 2026-05-12: advisory