Security readout for executives and security teams
Plain-English summary
CVE-2020-1100 is a SharePoint cross-site scripting issue. An attacker with some access could use a specially crafted web request and user interaction to run script in another user's browser context, potentially exposing limited data or changing limited actions in SharePoint.
Executive priority
Treat as a planned remediation priority, higher for internet-facing or widely used SharePoint portals. The issue is not listed as actively exploited in the supplied evidence, but affected legacy systems should not remain unpatched.
Technical view
Microsoft describes improper sanitization of a specially crafted web request in affected SharePoint servers. CVSS 3.1 is 5.4, network reachable, low attack complexity, low privileges required, user interaction required, scope changed, with low confidentiality and integrity impact and no availability impact.
Likely exposure
Exposure is most likely in organizations running Microsoft SharePoint Enterprise Server 2016 or 2013 SP1, or Microsoft SharePoint Server 2019 or 2010 SP2, especially where SharePoint is reachable by many users or exposed externally.
Exploitation context
The supplied sources do not show CISA KEV listing or other evidence of active exploitation. The vulnerability is still relevant for unpatched legacy or on-premises SharePoint deployments because XSS can support phishing, session abuse, or unauthorized user-context actions.
Researcher notes
This is CWE-79 XSS and is unique from CVE-2020-1099, CVE-2020-1101, and CVE-2020-1106. Source evidence does not include exploit details, proof-of-concept status, or named mitigations beyond consulting Microsoft guidance.
Mitigation direction
- Identify affected SharePoint versions in the environment.
- Check the Microsoft MSRC advisory for the applicable security update.
- Apply the vendor-recommended update for each exact SharePoint version.
- Reduce unnecessary external exposure to affected SharePoint sites.
- Review permissions for low-privileged accounts and untrusted contributors.
Validation and detection
- Inventory SharePoint Server and Enterprise Server versions.
- Compare installed build and patch levels against Microsoft guidance.
- Confirm affected public routes require appropriate authentication.
- Review SharePoint logs for unusual crafted request patterns.
- Validate that security updates are present in staging and production.
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-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupCVE-2020-1100 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
- 5.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1100CVE 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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.