Patch tracker / CVE reference / CVE-2026-55144

CVE-2026-55144

CVE-2026-55144 is a high severity Microsoft vulnerability with a CVSS score of 7.1. Its EPSS score puts the probability of exploitation in the next 30 days at 64%. 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

High

7.1

CVSS

64%

EPSS, 30 days

High

Severity

Not in the CISA KEV catalog. EPSS exploit probability 64%. CVSS 7.1 (High).

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

Senserva AI Opinion for CVE-2026-55144

CVE-2026-55144 is a tampering flaw in the Windows Cryptography API: Next Generation (CNG), the layer applications rely on for signing and key protection, so a successful tamper undermines integrity guarantees rather than just crashing a service. Exposure is narrow but notable: Windows Server 2022, Windows Server 2025 Server Core, and Windows 11 25H2 on ARM64, meaning headless server hosts and ARM devices are in scope. It carries Severity High with a CVSS score of 7.1, and it is not on the CISA KEV list nor tied to ransomware yet.

Do this: Deploy the CNG patch to your Server 2022, Server 2025 Server Core, and Windows 11 25H2 ARM64 systems, prioritizing hosts that perform signing or certificate operations.

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

Senserva AI Opinion and rich prompt for CVE-2026-55144

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-2026-55144 (source: https://senserva.com/cve/CVE-2026-55144.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-55144: High severity Microsoft vulnerability, CVSS 7.1
- EPSS 30-day exploitation probability: 64%
- Actively exploited (CISA KEV): no
- Fixed by: KB5099536, KB5099540, KB5101649, KB5101650
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 64%).

Fixed by KB5099536 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-2026-55144

High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5099536, KB5099540, KB5101649, KB5101650 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-2026-55144. 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.

KB5099536 KB5099540 KB5101649 KB5101650

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-56155 CVE-2026-32202 CVE-2026-50302 CVE-2026-50416 CVE-2026-50419 CVE-2026-57092 CVE-2026-42990 CVE-2026-49172

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.