Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
- Vendor
- Microsoft
- Product
- SharePoint
- CVSS
- 9.8
- EPSS (exploit probability)
- 29.2%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2026-20963 being exploited?
Yes. CISA added CVE-2026-20963 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. It is also listed in ENISA's EU Vulnerability Database (EUVD) exploited list.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 29.2% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ LISTED ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2026-20963 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by (3 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Microsoft SharePoint CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-65660 Microsoft SharePoint Code Injection Vulnerabilitywrite-up | [ HIGH ] | 8.8 | 9.9% | |
| CVE-2026-55040 SharePoint Server JWT token authentication bypasswrite-up | [ CRITICAL ] | 9.1 | 69.5% | |
| CVE-2026-50522 SharePoint Server deserialization of untrusted data RCEwrite-up | [ CRITICAL ] | 9.8 | 3.0% | |
| CVE-2026-58644 Microsoft SharePoint deserialization of untrusted data (unauth RCE)write-up | [ CRITICAL ] | 9.8 | 15.9% | |
| CVE-2026-56164 SharePoint Server elevation of privilege — missing authentication for critical functionwrite-up | [ MEDIUM ] | 5.3 | 27.3% | |
| CVE-2026-45659 Microsoft SharePoint Server deserialization remote code executionransomware usewrite-up | [ HIGH ] | 8.8 | 80.2% | |
| CVE-2026-32201 SharePoint Server spoofing via improper input validationwrite-up | [ MEDIUM ] | 6.5 | 44.0% | |
| CVE-2025-49706 Microsoft SharePoint Improper Authentication Vulnerabilityransomware use | [ MEDIUM ] | 6.5 | 99.9% |