Quick answers
- Is CVE-2026-48579 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-48579 being exploited in the wild.
- How severe is CVE-2026-48579?
- Critical severity, with a CVSS score of 9.1, published 4 June 2026.
- Which products and versions are affected?
- Microsoft Exchange Online.
- Is there a fix for CVE-2026-48579?
- 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-2026-48579 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-48579?
- Check whether you run Microsoft Exchange Online. 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 vulnerability classified as Improper Authorization (CWE-285) exists in Microsoft Exchange Online. The flaw allows a remote, unauthenticated attacker to bypass authorization checks and disclose sensitive information over the network. According to the CVSS vector, the attack complexity is low and requires no user interaction, posing a high risk to data confidentiality and integrity. As this is an exclusively hosted service, Microsoft typically manages the deployment of fixes directly within the Exchange Online environment.
Affected products
- Microsoft Exchange Online
Timeline
- 2026-06-04: advisory: Initial advisory published by Microsoft and NVD.