Security readout for executives and security teams
Plain-English summary
CMSimple 5.4 and earlier have a cross-site scripting issue where encoded input can bypass filtering. If a victim interacts with affected delete-button functionality, attacker-supplied JavaScript may run in the victim’s browser. This is a medium business risk, mainly affecting sites using CMSimple with exposed administrative or content-management workflows.
Executive priority
Treat as a targeted web-application risk, not an emergency unless CMSimple administration is internet-exposed or used by many staff. Prioritize asset identification, vendor guidance review, and reducing access to administrative workflows.
Technical view
CVE-2021-47733 is CWE-79 XSS in CMSimple <=5.4. The reported issue involves HTML-to-Unicode encoding bypassing input filtering, enabling script injection that executes when users interact with delete buttons. CVSS 3.1 is 6.1: network reachable, low complexity, no privileges, user interaction required, changed scope, low confidentiality and integrity impact.
Likely exposure
Exposure is limited to organizations running CMSimple version 5.4 or earlier. Public internet-facing CMSimple sites with users performing content administration or deletion actions are more relevant. No evidence in the provided sources identifies other products or versions.
Exploitation context
A public Exploit-DB entry exists, so proof-of-concept information is publicly available. The source bundle does not indicate CISA KEV listing or confirmed active exploitation. Successful exploitation requires user interaction and appears tied to affected delete-button behavior.
Researcher notes
The provided record names CMSimple <=5.4 and describes a filter-bypass XSS using Unicode encoding. Avoid assuming a fixed version; the supplied sources do not state one. Public exploit availability raises validation priority, but active exploitation is not supported by the provided evidence.
Mitigation direction
- Inventory CMSimple deployments and identify versions 5.4 or earlier.
- Check CMSimple and advisory sources for vendor-provided fixes or upgrade guidance.
- Limit administrative access to trusted users and trusted networks where feasible.
- Review content-management inputs for untrusted or encoded script-like data.
- Prioritize remediation for public-facing CMSimple administration interfaces.
Validation and detection
- Confirm whether any CMSimple deployment is version 5.4 or earlier.
- Review CMSimple web roots, admin panels, and asset fingerprints for version evidence.
- Check logs for suspicious encoded input submitted to CMSimple workflows.
- Validate remediation against vendor guidance when an official fix path is confirmed.
- Document whether affected delete-button workflows are reachable by untrusted users.
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-2021-47733 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
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-50612CVE reference · exploit
- CMSimple Official HomepageCVE reference · product
- VulnCheck Advisory: CMSimple 5.4 Cross-Site Scripting via HTML Unicode EncodingCVE reference · third-party-advisory
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.