CVE
Privilege Escalation
- Exploited
- No known exploitation
- Fix
- Fixed in 4818
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. M365 Manager Plus builds 4817 and earlier are affected.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 1.66% · 77th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 18/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Zohocorp M365 Manager Plus contains a privilege escalation flaw in its delegated administration interface, where insufficient permission checks let a logged-in technician-level user exceed their intended scope and possibly run code remotely. The attack can be carried out over the network by a user with low-privilege login access and needs no action from anyone else.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Zohocorp ManageEngine M365 Manager Plus versions below 4818 is affected by an authenticated technician may exploit insufficient permission validation in the delegated administration interface to escalate privileges beyond their intended scope, which could result in remote code execution during administrative processing.
Who should check
Teams running ManageEngine M365 Manager Plus builds 4817 and earlier, especially those with technician accounts using the delegated administration interface.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.9/10CVSS 9.9
- No patch0/5No signal
What would change the score
- Would score about 68 if added to CISA KEV
- Would score about 63 if CISA's SSVC rates exploitation active
- Would score about 25 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
M365 Manager Plus builds 4817 and earlier are affected.Upgrade to a fixed version: 4818.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-12591 (Privilege Escalation), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-12591 (entry last updated 2026-11-12):
Affected:
- Zohocorp M365 Manager Plus: fixed in 4818
Fixed versions: 4818.
Conditions (all must be true for the bug to be hit):
- M365 Manager Plus builds 4817 and earlier are affected. (source: https://www.manageengine.com/microsoft-365-management-reporting/CVE-2026-12591.html)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-12591 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-12591 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.manageengine.com/microsoft-365-management-reporting/CVE-2026-12591.html
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-12591
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-12591"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- Zohocorp M365 Manager Plus
fixed in 4818
Evidence 3
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 1
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-12591
Is CVE-2026-12591 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
An authenticated technician could gain administrator access and escalate privileges beyond their intended scope. The advisory says this could lead to remote code execution on the server.Source: manageengine.com
Which versions are affected by CVE-2026-12591?
M365 Manager Plus: before 4818.Source: cve.now feed data
Am I affected, and how do I check?
M365 Manager Plus builds 4817 and earlier are affected. To check a build, look at the build number shown for the installed M365 Manager Plus instance.Source: manageengine.com
How do I fix CVE-2026-12591?
Update M365 Manager Plus to build 4818 or later.Source: manageengine.com