CVE-2026-45659

Microsoft SharePoint ServerActively Exploited (CISA KEV)CVSS 8.8KEV0-Day

Actively exploited (CISA KEV) - patch before 2026-07-04

Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.

Actively exploited in the wild and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. No distribution fix is listed yet; apply vendor mitigations and monitor.

Recommended action: No fix is published yet for an actively-exploited flaw. Apply vendor mitigations, restrict exposure, and watch for a patch.

CVE-2026-45659 Microsoft SharePoint Server Actively Exploited (CISA KEV)

Severity metrics

CVSS 3.1 : 8.8 HIGH

Attack vectorNetwork (remote)

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeUnchanged

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Vector: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected & fixed versions by distribution

Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.

No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.

Sources

Advisory NVD CVE.org

Published 2026-07-04