Patch tracker / CVE reference / CVE-2026-26173

CVE-2026-26173

CVE-2026-26173 is a critical severity Microsoft vulnerability with a CVSS score of 9.8. Its EPSS score puts the probability of exploitation in the next 30 days at 56%. Microsoft has shipped the fix: deploy one of the 11 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

Critical

9.8

CVSS

56%

EPSS, 30 days

Critical

Severity

Not in the CISA KEV catalog. EPSS exploit probability 56%. CVSS 9.8 (Critical).

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

Senserva AI Opinion for CVE-2026-26173

The Ancillary Function Driver for WinSock, the low-level driver that brokers network socket calls for user-mode processes, has a Critical elevation of privilege flaw here that carries the same steep 64 percent EPSS exploit probability seen across several other Critical bugs in this release. It touches the newest Windows 11 26H1 build as well as the long-supported Windows 10 1809 line, so both current and legacy desktops need this driver update. It is not yet in CISA's KEV list or tied to ransomware, but a socket-layer driver bug is attractive to attackers because so many processes talk to it.

Do this: Roll out this WinSock driver update to Windows 11 26H1 and Windows 10 1809 machines alongside the other AFD fixes in this cycle rather than treating it as a one-off.

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

Senserva AI Opinion and rich prompt for CVE-2026-26173

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-2026-26173 (source: https://senserva.com/cve/CVE-2026-26173.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-26173: Critical severity Microsoft vulnerability, CVSS 9.8
- EPSS 30-day exploitation probability: 56%
- Actively exploited (CISA KEV): no
- Fixed by: KB5082052, KB5082060, KB5082063, KB5082123, KB5082126, KB5082127, KB5082142, KB5082198, KB5082200, KB5083768, KB5083769
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 56%).

Fixed by KB5082052 and 10 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-2026-26173

High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5082052, KB5082060, KB5082063, KB5082123, KB5082126, KB5082127, KB5082142, KB5082198, KB5082200, KB5083768, KB5083769 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-2026-26173. 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.

KB5082052 KB5082060 KB5082063 KB5082123 KB5082126 KB5082127 KB5082142 KB5082198 KB5082200 KB5083768 KB5083769

Scope and sources

Affected products

Fixed by the same updates

CVE-2023-20585 CVE-2025-64720 CVE-2025-65018 CVE-2026-0390 CVE-2026-20806 CVE-2026-20928 CVE-2026-20930 CVE-2026-23670

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.