Security readout for executives and security teams
Plain-English summary
CVE-2026-26114 is a high-severity SharePoint Server flaw that can let a logged-in attacker run code on the server over the network. For organizations using affected on-premises SharePoint, this could lead to data theft, tampering, or service disruption if not patched.
Executive priority
Treat as a near-term patching priority for affected SharePoint servers. The risk is serious because successful exploitation could compromise the server, but current provided evidence does not indicate active exploitation or unauthenticated access.
Technical view
Microsoft describes this as deserialization of untrusted data in Microsoft Office SharePoint. It affects SharePoint Enterprise Server 2016 and SharePoint Server 2019. CVSS 3.1 is 8.8, with network attack vector, low complexity, low privileges required, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to organizations running affected Microsoft SharePoint Enterprise Server 2016 or SharePoint Server 2019 instances, especially network-reachable deployments where authenticated users can access SharePoint services.
Exploitation context
The source bundle does not show known active exploitation. CISA KEV status is false, and the CVSS exploit maturity is listed as unproven. Exploitation requires an authorized attacker, not an unauthenticated internet user based on the provided data.
Researcher notes
Key constraints are PR:L and UI:N. The vulnerability class is CWE-502 deserialization of untrusted data. Public details in the provided sources do not include root-cause specifics, proof-of-concept status, exploit telemetry, or detailed remediation beyond Microsoft’s advisory.
Mitigation direction
- Review Microsoft’s CVE-2026-26114 advisory and apply the provided SharePoint security update.
- Prioritize externally reachable or broadly accessible SharePoint farms.
- Restrict SharePoint access to required users and trusted networks where feasible.
- Monitor Microsoft guidance for any updated workarounds or superseding patches.
Validation and detection
- Inventory SharePoint Enterprise Server 2016 and SharePoint Server 2019 deployments.
- Confirm installed SharePoint build and security update level against Microsoft’s advisory.
- Verify vulnerable servers are not exposed beyond business requirements.
- Review SharePoint and authentication logs for unusual authenticated activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-26114 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft SharePoint Server Remote Code Execution VulnerabilityCVE reference · vendor-advisory, patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.