KEV Lag Tracker → CVE-2026-56155. Data verified against the official CISA KEV catalog and the National Vulnerability Database.
CISA added CVE-2026-56155 (Microsoft Active Directory Federation Services) to the Known Exploited Vulnerabilities catalog on July 14, 2026. CISA listed it as actively exploited 0 days before its NVD publication date — exploitation was confirmed at or before public disclosure. A KEV listing is CISA’s official confirmation that a vulnerability is being exploited in the wild.
The Record
| CVE | CVE-2026-56155 |
| Vendor / product | Microsoft Active Directory Federation Services |
| Vulnerability | Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability |
| CVSS base score | 7.8 |
| NVD publication date | July 14, 2026 |
| Added to CISA KEV | July 14, 2026 |
| Lag (public → KEV listing) | 0 days |
| Federal patch deadline | July 28, 2026 |
| Known ransomware use | No |
Measured against the 1665 entries in our tracker with verified publication dates, CVE-2026-56155 was flagged faster than 87% of them.
What CISA Reported
CISA describes the flaw as follows: “Microsoft Active Directory Federation Services contains an insufficient granularity of access control vulnerability that allows an authorized attacker to elevate privileges locally.”
Federal Patch Deadline
Under Binding Operational Directive rules, U.S. federal agencies must remediate CVE-2026-56155 by July 28, 2026 — a 14-day remediation window from the KEV listing date. Private organizations are not bound by that deadline; CISA treats it as the benchmark for how urgently a confirmed-exploited flaw should be patched.
How This Compares to Microsoft’s Track Record
At 0 days, CVE-2026-56155 was flagged faster than Microsoft’s 567-day median across the 383 of its KEV entries with verified publication dates. Microsoft currently ranks #18 on our KEV Lag leaderboard.
| Microsoft in the CISA KEV catalog | Value |
|---|---|
| Tracked KEV entries | 383 |
| Median lag (public → KEV listing) | 567 days |
| 0-day rate (exploited at or before disclosure) | 23% |
| Entries tied to known ransomware campaigns | 104 |
Other Recent Microsoft KEV Additions
| CVE | Product | Added to KEV | Lag (days) | Ransomware |
|---|---|---|---|---|
| CVE-2026-68820 | Windows Ancillary Function Driver for WinSock | August 11, 2026 | 0 | No |
| CVE-2026-50522 | SharePoint | July 22, 2026 | 8 | No |
| CVE-2026-58644 | SharePoint | July 16, 2026 | 2 | No |
| CVE-2026-56164 | SharePoint Server | July 14, 2026 | 0 | No |
| CVE-2026-45659 | SharePoint Server | July 1, 2026 | 40 | No |
Defense guide: How to Detect Zero-day Vulnerability: Attack Chain & Defense — detection signals, attack chain and response steps for this class of attack.
Frequently Asked Questions
What is CVE-2026-56155?
CVE-2026-56155 is a vulnerability in Microsoft Active Directory Federation Services (Microsoft Active Directory Federation Services Insufficient Granularity of Access Control Vulnerability ) that CISA added to its Known Exploited Vulnerabilities catalog on July 14, 2026. A KEV listing is CISA’s official confirmation that the flaw is being exploited in the wild.
How long was CVE-2026-56155 public before CISA confirmed exploitation?
0 days before its NVD publication date — CISA listed it as exploited at or before the vulnerability was formally published, which is the signature of a zero-day.
What is the federal patch deadline for CVE-2026-56155?
U.S. federal agencies must remediate CVE-2026-56155 by July 28, 2026, a 14-day window from the KEV listing date. Private organizations are not bound by that deadline, but CISA treats it as the benchmark for how urgently a confirmed-exploited flaw should be patched.
Is CVE-2026-56155 used in ransomware campaigns?
CISA has not flagged CVE-2026-56155 as known to be used in ransomware campaigns. That field reflects confirmed campaign use, not the absence of risk.
How does this compare to other Microsoft vulnerabilities?
Across 383 Microsoft entries with verified publication dates, the median lag is 567 days and 23% were exploited at or before disclosure. CVE-2026-56155, at 0 days, is faster than that median.
Related Coverage
- Critical Microsoft SharePoint Flaw CVE-2026-50522 (CVSS 9.8) Added to CISA KEV (July 2026)
- WordPress’s CVE-2026-63030 Was Exploited in 4 Days — Well Under Its 420-Day Median (July 2026)
Primary Sources
- CISA Known Exploited Vulnerabilities Catalog — the official listing that confirms active exploitation, and the source of the KEV date on this page.
- NVD — CVE-2026-56155 — publication date, CVSS score and the full technical record.
- Vendor advisory — msrc.microsoft.com — Microsoft’s own disclosure, with the affected versions and the fix.
- Vendor advisory — learn.microsoft.com — Microsoft’s own disclosure, with the affected versions and the fix.
How We Track This
This page is generated from our CISA KEV Lag Tracker, which syncs the official CISA KEV catalog daily and records the date each CVE is added. For every entry we retrieve the original NVD publication date and compute the lag in calendar days. No date or figure on this page is estimated or taken from a third-party source — they come directly from CISA and NVD records. Free to cite with attribution to CVEDaily (CC BY 4.0).