Quick answers
- Is CVE-2026-118153 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-118153 being exploited in the wild.
- How severe is CVE-2026-118153?
- High severity, with a CVSS score of 7.5, published 10 November 2026.
- Which products and versions are affected?
- Microsoft Exchange Server.
- Is there a fix for CVE-2026-118153?
- 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-2026-118153 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-118153?
- Check whether you run Microsoft Exchange Server. 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
The vulnerability stems from inefficient algorithmic complexity in Microsoft Exchange Server that allows an unauthenticated network-based attacker to trigger excessive resource consumption and cause denial of service. No authentication or user interaction is required; the attacker can send specially crafted network requests to exhaust server resources and render the service unavailable.
Affected products
- Microsoft Exchange Server
Timeline
- 2026-11-10: disclosed