Affects Microsoft SharePoint, a widely deployed enterprise collaboration platform; allows remote code execution and potential full infrastructure compromise.
CVE-2026-58644
Remote code execution in Microsoft SharePoint via deserialization of untrusted data.
Is CVE-2026-58644 being exploited?
Yes. CVE-2026-58644 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2026-58644?
CVE-2026-58644 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-58644?
Yes. A fix has been recorded for CVE-2026-58644. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-58644 affect?
CVE-2026-58644 affects Microsoft SharePoint (on‑premises Server), Microsoft SharePoint Online (potential). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-58644?
Apply vendor patch immediately; if unavailable, isolate SharePoint and restrict network access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote code execution by sending crafted serialized payloads to SharePoint, enabling full system compromise and lateral movement.
Immediate action required
- affected>= 16.0.0 and < 16.0.5556.1005
- affected>= 16.0.0 and < 16.0.10417.20153
- affected>= 16.0.0 and < 16.0.19725.20384
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.