Security readout for executives and security teams
Plain-English summary
This high-severity SharePoint Server flaw could let an authenticated attacker run code remotely, potentially compromising sensitive information, altering content, or disrupting service. Exploitation requires authorized access but no user interaction. The supplied evidence does not establish active exploitation.
Executive priority
Treat as a high-priority patching item. Confirm affected SharePoint Server deployments, prioritize accessible systems, and require evidence that Microsoft's applicable update is installed. Escalate faster where SharePoint contains sensitive data or supports critical operations.
Technical view
CVE-2026-35439 is CWE-502: deserialization of untrusted data. It is network-accessible, low-complexity, requires low privileges, and requires no user interaction. Successful exploitation can fully affect confidentiality, integrity, and availability. CVSS 3.1 is 8.8.
Likely exposure
Exposure applies to deployments of SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition identified in the supplied record. Risk is greatest where authenticated accounts can reach vulnerable SharePoint services. The bundle does not provide configuration-specific prerequisites or detection indicators.
Exploitation context
The bundle marks this CVE as absent from KEV and gives an unproven exploit-maturity metric. No supplied source supports active exploitation. Because an attacker needs authorized access, compromised or malicious low-privilege accounts are the relevant threat context.
Researcher notes
The supplied material identifies unsafe deserialization but provides no vulnerable component, attack path, indicators, or configuration qualifiers. CVSS indicates network reachability, low complexity, low privileges, no user interaction, unchanged scope, and high impact across all three security objectives. Avoid inferring additional affected products or exploitation activity.
Mitigation direction
- Review the Microsoft advisory and apply its applicable security update promptly.
- Prioritize externally reachable or broadly accessible SharePoint Server deployments.
- Restrict SharePoint access and privileges until remediation is verified.
- Monitor Microsoft guidance for revised mitigations or affected-version details.
Validation and detection
- Inventory the listed SharePoint Server products and deployed build levels.
- Compare installed updates against the Microsoft advisory's applicable security update.
- Confirm vulnerable services are not unnecessarily exposed to untrusted networks.
- Review authentication and SharePoint telemetry for suspicious authenticated activity.
- Retest service availability and security-update status after remediation.
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-2026-35439 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.
SSVC decision data
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:C2.85.9microsoftVulnerability 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft SharePoint Server Remote Code Execution VulnerabilityCVE reference, microsoft · 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.