Security readout for executives and security teams
Plain-English summary
CVE-2021-31948 is a high-severity spoofing issue in Microsoft SharePoint Server. In practical terms, a logged-in attacker could abuse SharePoint behavior in a way that may expose sensitive information or slightly affect integrity, but the CVSS data indicates user interaction is required.
Executive priority
Prioritize remediation in normal high-severity patch cycles, accelerated for internet-facing or sensitive SharePoint environments. The business risk is potential exposure of confidential SharePoint data, but the provided evidence does not justify emergency active-exploitation response language.
Technical view
The provided CVSS 3.1 vector is 7.6: network attack, low complexity, low privileges required, user interaction required, changed scope, high confidentiality impact, low integrity impact, and no availability impact. The affected products listed are SharePoint Foundation 2013 SP1, SharePoint Enterprise Server 2016, and SharePoint Server 2019.
Likely exposure
Exposure is most likely in organizations running the listed on-premises SharePoint products, especially where low-privileged users can access SharePoint and interact with targeted content. The bundle does not list SharePoint Online or other Microsoft products as affected.
Exploitation context
The source bundle does not show CISA KEV inclusion, and the CVSS exploit maturity is unproven. There is no cited evidence here of active exploitation. Treat this as a real patch-management concern, not as confirmed in-the-wild exploitation.
Researcher notes
The public details in the bundle are sparse: Microsoft classifies this as spoofing, with high confidentiality impact and required user interaction. Avoid assumptions about exploit mechanics. Validation should focus on product presence, build status, access exposure, and Microsoft advisory alignment.
Mitigation direction
- Review the Microsoft MSRC advisory for official remediation guidance.
- Prioritize affected internet-facing or broadly accessible SharePoint deployments.
- Apply Microsoft-provided SharePoint security updates where applicable.
- Restrict SharePoint access to necessary users and networks.
- Monitor vendor guidance for any revised affected-version or remediation details.
Validation and detection
- Inventory SharePoint Foundation 2013 SP1, Enterprise Server 2016, and Server 2019 instances.
- Compare installed SharePoint builds against Microsoft’s CVE-2021-31948 guidance.
- Identify deployments reachable by untrusted or low-privileged users.
- Confirm patch status through existing vulnerability management tooling.
- Review SharePoint logs for unusual access patterns, without assuming exploitation.
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-2021-31948 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
- 7.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/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:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N/E:U/RL:O/RC:C2.34.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.6HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/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-2021-31948CVE 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.