Patch tracker / CVE reference / CVE-2026-56155

CVE-2026-56155

CVE-2026-56155 is a high severity Microsoft vulnerability with a CVSS score of 7.8. It is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it in the wild, which makes it a fix-first item. Microsoft has shipped the fix: deploy one of the 6 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

HighCISA KEV

7.8

CVSS

64%

EPSS, 30 days

High

Severity

Yes

Exploited in the wild

Listed in the CISA Known Exploited Vulnerabilities catalog, confirmed exploited in the wild. EPSS exploit probability 64%. CVSS 7.8 (High).

This CVE is among the top half of tracked Microsoft CVEs by EPSS exploit probability, and one of 3 actively-exploited CVEs in July 2026.

Senserva Watchevery change we have recorded for this one

What changed, and when

The strongest signal is CISA KEV inclusion on 2026-07-14, confirming active exploitation before any EPSS score existed. Severity then jumped from 7.8 to 9.9 on 2026-07-23, and EPSS climbed from 0.0% to 7.5% that same day, reaching 11.1% on 2026-07-24. The direction is sharply upward, so prioritize patching today.

Drawn by Senserva Vivid from the Senserva change record. Hover any point for its date and value.

2026-07-14 added to the CISA KEV catalog by CISA
2026-07-17 EPSS first scored at 0.0%
2026-07-23 CVSS 7.8 to 9.9; EPSS 0.0% to 7.5%
2026-07-24 EPSS 7.5% to 11.1%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

Senserva AI Opinion and rich prompt for CVE-2026-56155

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-2026-56155 (source: https://senserva.com/cve/CVE-2026-56155.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-56155: High severity Microsoft vulnerability, CVSS 7.8
- EPSS 30-day exploitation probability: 64%
- Actively exploited (CISA KEV): YES
- Fixed by: KB5099444, KB5099445, KB5099535, KB5099536, KB5099538, KB5099540
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 now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

Fixed by KB5099444 and 5 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Patch now and verify deployment on every exposed device.

Official patch(es) for CVE-2026-56155

Treat as urgent: it is being exploited in the wild (CISA KEV), so patch ahead of items that are not. In Intune or Defender, confirm whether the fixing updates KB5099444, KB5099445, KB5099535, KB5099536, KB5099538, KB5099540 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-2026-56155. 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.

KB5099444 KB5099445 KB5099535 KB5099536 KB5099538 KB5099540

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-32202 CVE-2026-50302 CVE-2026-50416 CVE-2026-50419 CVE-2026-57092 CVE-2026-42990 CVE-2026-49172 CVE-2026-50447

Authoritative references

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

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