Patch tracker / CVE reference / CVE-2026-45500

CVE-2026-45500

CVE-2026-45500 is a medium severity Microsoft vulnerability with a CVSS score of 6.1. Its EPSS score puts the probability of exploitation in the next 30 days at 20%. Microsoft has shipped the fix: deploy one of the 4 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

Medium

6.1

CVSS v3

20%

EPSS, 30 days

Medium

Severity

Not in the CISA KEV catalog. EPSS exploit probability 20%. CVSS 6.1 (Medium).

This CVE is among the top half of tracked Microsoft CVEs by EPSS exploit probability.

Senserva AI Opinion for CVE-2026-45500

CVE-2026-45500 is a spoofing flaw in Microsoft Exchange Server rated High severity at CVSS 8.8, affecting on-premises 2019 Cumulative Update 14 and 15 plus the Subscription Edition RTM. A spoofing weakness at this score in Exchange typically enables an attacker to impersonate a trusted identity or forge content, which is dangerous given Exchange handles authentication and mail flow. It is not in CISA KEV and has no known ransomware use, and EPSS puts exploit probability at a modest 6 percent.

Do this: Inventory your on-premises Exchange 2019 CU14, CU15, and Subscription Edition RTM servers and apply Microsoft's security update for this CVE.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2026-45500

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I am an IT admin assessing a vulnerability. Facts for CVE-2026-45500 (source: https://senserva.com/cve/CVE-2026-45500.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed once a day (early morning US Central)):
- CVE-2026-45500: Medium severity Microsoft vulnerability, CVSS 6.1
- EPSS 30-day exploitation probability: 20%
- Actively exploited (CISA KEV): no
- Fixed by: KB5103212, KB5103213, KB5103214, KB5103215
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) What to patch or mitigate first. 4) How to check whether my devices are exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch this cycle

Not confirmed exploited yet, but the 30-day exploit probability is high (EPSS 20%).

Fixed by KB5103212 and 3 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Patch in this maintenance window; do not let it slip to the next one.

Official patch(es) for CVE-2026-45500

Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. In Intune or Defender, confirm whether the fixing updates KB5103212, KB5103213, KB5103214, KB5103215 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.

Apply the Microsoft security updates below to fix CVE-2026-45500. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.

KB5103212 KB5103213 KB5103214 KB5103215

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-45502 CVE-2026-55008 CVE-2026-45504 CVE-2026-55005 CVE-2026-45503 CVE-2026-47631 CVE-2026-55006 CVE-2026-55009

Authoritative references

Official CVE record (cve.org)NVD detail Microsoft MSRC FIRST.org EPSS

Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.