---
id: "CVE-2026-118153"
page: "https://infrastack.ai/live/CVE-2026-118153"
kind: "vulnerability"
aliases: ["CVE-2026-118153"]
title: "Microsoft Exchange Server Subscription Edition: unauthenticated network denial of service (fixed in 15.02.2562.057)"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Exchange Server Subscription Edition RTM", "fixed": ["15.02.2562.057"], "affected": ">= 15.02.0.0, < 15.02.2562.057", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exchange-server", "infrastructure", "self-hosted", "subscription-edition", "windows"]
not_affected_if: ["exchange-online"]
published_at: "2026-11-10T19:19:37+00:00"
first_seen_at: "2026-11-10T19:24:49+00:00"
updated_at: "2026-11-10T23:22:17+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118153", "first_seen_at": "2026-11-10T19:24:49+00:00"}, {"source": "analyst", "url": "https://cveawg.mitre.org/api/cve/CVE-2026-118153", "first_seen_at": "2026-11-10T23:22:17+00:00", "cites": ["https://cveawg.mitre.org/api/cve/CVE-2026-118153"]}]
exploit_sources: []
---

# Microsoft Exchange Server Subscription Edition: unauthenticated network denial of service (fixed in 15.02.2562.057)

Link for people: https://infrastack.ai/live/CVE-2026-118153 (this .md is for agents)

Microsoft Exchange Server has an inefficient algorithm that an unauthorized attacker can trigger over the network. The result is a denial of service, taking the mail server offline or degrading it.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Exchange Server Subscription Edition RTM affected >= 15.02.0.0, < 15.02.2562.057 fixed 15.02.2562.057

## How to check

On each Exchange SE server run in Exchange Management Shell: Get-ExchangeServer | Format-List Name,AdminDisplayVersion. Exposed if the build is below 15.02.2562.057.

## Fix

Update Exchange Server Subscription Edition RTM to build 15.02.2562.057 or later (November 2026 security update); see the MSRC entry for the KB.

## Timeline

- 2026-11-10T19:24:49+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118153
- 2026-11-10T23:22:17+00:00 analyst https://cveawg.mitre.org/api/cve/CVE-2026-118153 — Microsoft CNA record (cve.org API) gives affected range for Exchange SE RTM; MSRC page is JS-only and unread; KB number only from third-party site, not recorded. No exploitation (CISA SSVC: none).

## Documents

- [advisory] CVE record CVE-2026-118153 (Microsoft CNA) https://cveawg.mitre.org/api/cve/CVE-2026-118153

## From the sources

Inefficient algorithmic complexity in Microsoft Exchange Server allows an unauthorized attacker to deny service over a network.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_