Back Senserva

CVE-2026-45503: the Microsoft Exchange Server Subscription fix is KB5094139 (CVSS 8.8)

Senserva • July 4, 2026

High severity Microsoft vulnerability, CVSS 8.8. Fixed by 4 Microsoft security updates.

CVE-2026-45503 is a high severity Microsoft vulnerability with a CVSS score of 8.8. 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.

Not in the CISA KEV catalog. EPSS exploit probability 5.6%. CVSS 8.8 (High).

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

Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing updates KB5094139, KB5094140, KB5094142, KB5094144 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-2026-45503. Each KB page links to the Microsoft Update Catalog download for every affected product.

It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the 30 days at 5.6%.

Microsoft fixed CVE-2026-45503 in KB5094139, KB5094140, KB5094142, KB5094144. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.

Microsoft Exchange Server 2019 Cumulative Update 14, Microsoft Exchange Server 2019 Cumulative Update 15, Microsoft Exchange Server Subscription Edition RTM.

If you are patching CVE-2026-45503, the same updates also fix these:

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

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Active Exploitation of Microsoft SharePoint Flaw CVE-2026-45659 Confirmed The US Cybersecurity and Infrastructure Security Agency (CISA) has added CVE-2026-45659, a remote code execution vulnerability in Microsoft SharePoint, to its Known Exploited Vulnerabilities catalog due to active exploitation. This flaw, stemming from an untrusted data deserialization issue, affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. Microsoft released a patch for this vulnerability on May 21, 2026, but details were inadvertently omitted from the update bulletin. Organizations using SharePoint are urged to verify their patch levels and implement incident response procedures if they have not updated. The vulnerability allows authenticated attackers with minimal privileges to exploit it, potentially granting access to sensitive resources. CISA has mandated that federal agencies patch this vulnerability by July 4, 2026, emphasizing the urgency of remediation for all exposed organizations. No specific incidents of exploitation have been reported yet. 2 sources 73

Extracted Entities

CVEs (1)

CVE-2026-45503

Platforms (1)

Microsoft Exchange Server