2026-004: Critical Vulnerability in SharePoint Exploited
On 17 March 2026, Microsoft updated one of its January 2026 security advisories related to a remote code execution vulnerability in Microsoft SharePoint. Specifically, Microsoft raised the CVSS score and changed the FAQ section to indicate that the vulnerability could be exploited by an unauthenticated attacker. This vulnerability was added in the CISA's Known Exploited Vulnerabilities (KEV) catalogue on 18 March 2026.<br>
Additionally, three further RCE flaws affecting Microsoft SharePoint were addressed in the March 2026 release.<br>
CERT-EU strongly recommends updating SharePoint servers as soon as possible, prioritising internet-facing assets. CERT-EU also encourages IT administrators to take necessary remediation actions.<br>
CRITICAL
Severity & confidence
Source severitycritical
Platform severitycritical
Confidencehigh
Exploitationunknown
CVSS-
Affected
CountriesEU
Reporting sources (1)
CERT-EU - Security Advisories
Timeline & provenance
Published2026-08-21T04:41:04
Last updated2026-09-25T15:29:08
Ingested2026-08-21T04:41:04
FreshnessNEAR-REAL-TIME
Threat typevulnerability
Recommended action
No recommended action published with this item - review the original source.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: gov ยท Original: CERT-EU - Security Advisories
