Quick answers
- Is CVE-2026-12591 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-12591 being exploited in the wild.
- How severe is CVE-2026-12591?
- Critical severity, with a CVSS score of 9.9, published 12 November 2026.
- Which products and versions are affected?
- Zoho ManageEngine M365 Manager Plus builds 4817 and earlier.
- Is there a fix for CVE-2026-12591?
- Yes: fixed in build 4818. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-12591 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-12591?
- Check whether you run Zoho ManageEngine M365 Manager Plus 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.
How to fix
- Fixed in: build 4818
Technical details
An authenticated privilege escalation vulnerability in M365 Manager Plus allows a technician to bypass authorization checks in delegated administration APIs to gain administrator access. An attacker with technician-level credentials can escalate privileges and achieve remote code execution during administrative processing. The fix implements proper authorization checks and input sanitization for the affected APIs.
Affected products
- Zoho ManageEngine M365 Manager Plus builds 4817 and earlier
Timeline
- 2026-11-12: disclosed
- 2026-06-24: patched: Fixed version 4818 released