CVE-2026-118151Microsoft Exchange Server Subscription Edition RTM external control of a file name
CVE-2026-118151 is a external control of a file name in Microsoft Exchange Server Subscription Edition RTM, rated high (7.2 on CVSS 3.1).
Why this priority: High severity, with no exploitation signal yet.
Published · Updated · NVD status: Awaiting Analysis
What it is
Input decides which file the software opens, so a caller can point it elsewhere.
How it is reached
An attacker can exploit it over the network, with an administrator account, and nobody has to click anything.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker read or write files outside the folders the service meant to expose.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade Microsoft Exchange Server Subscription Edition RTM to 15.02.2562.057 or later.
- Until it is patched, review who holds accounts that can reach it.
Description from NVD
External control of file name or path in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- File storage the service can read or write. The flaw sits between the application and the file system it can reach.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- Between the application and the file system it can reach. An attacker who crosses it can read or write files outside the folders the service meant to expose.
Questions to answer about your own systems
- Where does Microsoft Exchange Server Subscription Edition RTM run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.