Exploited· due 2026-07-04used in ransomware
CVE-2026-45659
Microsoft SharePoint Server
Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.
Exploitation status
- CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
- It is known to have been used in ransomware campaigns.
- US federal civilian agencies are required to remediate it by 2026-07-04. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.
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.
CISA’s wording, unedited.
Scoring
- CVSS
- Not yet scored
Dates
- Published
- 2026-07-01
- Added to KEV
- 2026-07-01
- Remediation due
- 2026-07-04
- Sources
- CISA KEV