Security readout for executives and security teams
Plain-English summary
This is a high-severity Microsoft SharePoint spoofing vulnerability affecting listed on-premises SharePoint versions. An attacker with low privileges could abuse it only with user interaction. The main business concern is potential exposure of sensitive SharePoint content, not service outage.
Executive priority
Treat this as high priority for affected SharePoint environments, especially where sensitive documents are stored. It is not KEV-listed in the provided data, so prioritize remediation through the normal high-severity patch process rather than emergency response unless local exposure is high.
Technical view
CVE-2021-31964 is rated CVSS 7.6 with network attack vector, low complexity, low privileges required, and user interaction required. Scope changes, confidentiality impact is high, integrity impact is low, and availability impact is none. Sources identify it only as a SharePoint Server spoofing vulnerability.
Likely exposure
Exposure is limited to organizations running Microsoft SharePoint Foundation 2013 SP1, SharePoint Enterprise Server 2016, or SharePoint Server 2019 versions listed in the CVE data. Internet-facing and broadly accessible internal SharePoint deployments deserve earlier review.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The CVSS vector indicates exploitation requires low privileges and user interaction, so this is not described as unauthenticated or wormable in the source bundle.
Researcher notes
The public bundle is sparse: no CWE, exploit narrative, or detailed attack mechanics are provided. Analysis should stay anchored to the CVSS vector and Microsoft advisory. Do not assume product versions beyond the listed affected SharePoint releases.
Mitigation direction
- Review Microsoft MSRC guidance for CVE-2021-31964.
- Apply the applicable official Microsoft SharePoint security update.
- Prioritize internet-facing or highly sensitive SharePoint farms.
- Restrict SharePoint access to required users where feasible.
- Monitor Microsoft guidance for any later deployment notes.
Validation and detection
- Inventory SharePoint 2013 SP1, 2016, and 2019 deployments.
- Confirm whether each deployment matches the affected products listed.
- Verify applicable Microsoft security updates are installed.
- Check whether SharePoint is internet-facing or broadly reachable.
- Review logs for suspicious SharePoint user activity if exposure was prolonged.
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-2021-31964 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-2021-31964CVE 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.