Widely deployed SharePoint; RCE risk could disrupt enterprise operations.
CVE-2026-20963
RCE via deserialization in Microsoft Office SharePoint.
Is CVE-2026-20963 being exploited?
Yes. CVE-2026-20963 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-2026-20963?
CVE-2026-20963 is rated High with a CVSS score of 8.8. 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-2026-20963?
Yes. A fix has been recorded for CVE-2026-20963. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-20963 affect?
CVE-2026-20963 affects Microsoft Office SharePoint Server, SharePoint Online (Microsoft 365). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-20963?
Apply latest SharePoint security updates.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution on SharePoint server via deserialization of untrusted data over the network.
Patch when possible
- affected>= 16.0.0 and < 16.0.5535.1001
- affected>= 16.0.0 and < 16.0.10417.20083
- affected>= 16.0.0 and < 16.0.19127.20442
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.