KEV · Actively exploited
CVE-2026-55040
CVE-2026-55040 is actively exploited (CISA KEV catalog) : critical severity (CVSS 9.1), 0 tracked apps concerned, none still exposed on their current version.
- Severity (CVSS)
- 9.1
- Exploitation
- Confirmed
- Tracked apps
- 0
- Still exposed
- 0
NVD scale
CISA KEV · EPSS predicts 39.7 %
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Attack vector : Network
No privileges required
No user interaction
Show raw CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
39.65%
predictive model; CISA confirms active exploitation
percentile 98.5%
CISA Known Exploited Vulnerability
- Added to KEV
- 2026-08-18
- Remediation deadline
- 2026-08-21
- Required action
- Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- Ransomware
- Unknown (not documented by CISA)