What it is
CVE-2026-20963 is an unauthenticated Microsoft SharePoint Remote Code Execution Vulnerability affecting Microsoft Microsoft SharePoint Enterprise Server 2016 and 2 other products. Deserialization of untrusted data in...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2026-20963
Microsoft SharePoint Remote Code Execution Vulnerability
Microsoft / Microsoft SharePoint Enterprise Server 2016 · affected before 16.0.5535.1001
- Severity
- CVSS 9.8 · Critical
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 31.1%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
Microsoft / Microsoft SharePoint Enterprise Server 2016 affected before 16.0.5535.1001.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Microsoft SharePoint Remote Code Execution Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Vendor
Product
Affected
Status
Microsoft
Microsoft SharePoint Enterprise Server 2016
Before 16.0.5535.1001
Affected
Microsoft
Microsoft SharePoint Server 2019
Before 16.0.10417.20083
Affected
Microsoft
Microsoft SharePoint Server Subscription Edition
Before 16.0.19127.20442
Affected
- Published
- 13 Jan 2026
- Exploitation Reported
- 01 Jun 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
cisa
microsoft
CVE References
- Microsoft SharePoint Remote Code Execution Vulnerability msrc.microsoft.com · Vendor Advisory https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CVE
Independent exploitation attestation added to the KEV Intelligence record.
Proof of concept available
GitHub
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 12:10 UTC |
| CISA | 2026-06-02 14:02 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
EPSS
31.1%
Weaknesses
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
jenniferreire26/CVE-2026-20963
github · Created 2026-03-27 21:03:46 UTC · 1 stars
Timeline
From disclosure to observed exploitation
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
Public PoC available
Public proof-of-concept code published
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2026-20963
Free JSON includes basic KEV fields{
"cve_id": "CVE-2026-20963",
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": 0.31139,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}