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Vulnerabilities

Vulnerability · CVE-2026-20963

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Published Jan 13, 2026 · catalog updated Jun 17, 2026 · Microsoft SharePoint

Patch now

CVE-2026-20963 is in the CISA known-exploited catalog, due Mar 21, 2026. Confirm Microsoft SharePoint against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
29.20%
Remediation
Remediation guidance
Affected products
cpe microsoft/sharepoint server · vendor Microsoft SharePoint

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe microsoft/sharepoint server2016
  • cpe microsoft/sharepoint server2019
  • vendor Microsoft SharePointversion unspecified

How to fix CVE-2026-20963

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-20963 is in the CISA known-exploited catalog, due Mar 21, 2026. Confirm Microsoft SharePoint against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with microsoft/sharepoint server 2016; microsoft/sharepoint server 2019. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-502: Deserialization of Untrusted Data. EPSS 29.20%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 13, 2026 · Catalog

    Detected

    Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

  2. Mar 18, 2026 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  3. Mar 21, 2026 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  4. Jun 17, 2026 · Catalog

    Updated

    Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

Sources

  • CISA KEVConfirmed exploitationCVE-2026-20963

    Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2026-20963

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-20963

    30-day exploitation probability 29.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-20963

    Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-20963

    Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.