Security readout for executives and security teams
Plain-English summary
CVE-2021-31171 is an information disclosure issue in specific on-premises Microsoft SharePoint versions. The main business risk is exposure of sensitive SharePoint data, but exploitation requires local access, high privileges, and high attack complexity, which lowers urgency compared with internet-facing remote flaws.
Executive priority
Handle in the standard vulnerability patch cycle, with faster action for SharePoint farms containing sensitive or regulated data. The issue has meaningful confidentiality impact, but the required local access and high privileges reduce immediate emergency urgency.
Technical view
The vulnerability affects SharePoint Foundation 2013 SP1, SharePoint Enterprise Server 2016, and SharePoint Server 2019. CVSS 3.1 is 4.1 with local attack vector, high complexity, high privileges required, no user interaction, and high confidentiality impact only.
Likely exposure
Exposure is most likely in organizations still operating affected on-premises SharePoint 2013 SP1, 2016 Enterprise, or 2019 servers. SharePoint Online is not listed in the provided affected products. Risk is higher where privileged local access is broadly available or SharePoint stores sensitive documents.
Exploitation context
The provided bundle does not show CISA KEV listing or cited active exploitation. CVSS exploit maturity is unproven. Treat this as a confidentiality risk requiring patch validation, not as evidence of active exploitation.
Researcher notes
Public detail in the provided bundle is limited to product scope, CVSS metadata, and Microsoft advisory linkage. No root cause, proof of concept, affected component, or exploit telemetry is provided here, so validation should focus on version and patch state.
Mitigation direction
- Review the Microsoft MSRC advisory for the official SharePoint security update guidance.
- Apply the relevant SharePoint security updates for each affected product version.
- Limit local and high-privilege access on SharePoint servers to required administrators.
- Audit privileged access paths to SharePoint hosts and supporting infrastructure.
- Prioritize sensitive-content farms before lower-value or isolated environments.
Validation and detection
- Inventory SharePoint servers and map them to the affected versions listed for this CVE.
- Confirm installed SharePoint security updates against Microsoft MSRC guidance.
- Check whether affected farms store regulated, confidential, or executive-sensitive content.
- Review administrative and local access assignments for unnecessary high-privilege users.
- Document patched, unaffected, and retired SharePoint instances for audit evidence.
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.
CVE-2021-31171 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
- Medium
- CVSS
- 4.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N/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:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C0.53.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.1MediumVector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31171CVE reference · x_refsource_MISC
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.