Security readout for executives and security teams
Plain-English summary
This is a stored cross-site scripting issue in Sourcecodetester Simple Client Management System 1.0. An authenticated attacker could save malicious script or HTML into vulnerable fields, which may later run in another user's browser. Business risk is moderate because exploitation needs privileges and user interaction, and sources do not show active exploitation.
Executive priority
Treat as a moderate-priority web application risk. It is not listed as actively exploited, but stored XSS can affect administrators or staff who view poisoned records. Prioritize if the application is internet-facing or used by many internal users.
Technical view
CVE-2021-43657 is CWE-79 stored XSS via MAster.php in SCMS 1.0. CVSS 3.1 is 5.4: network exploitable, low complexity, low privileges required, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact. Structured affected-product metadata is incomplete.
Likely exposure
Exposure is likely limited to organizations running Sourcecodetester Simple Client Management System 1.0, especially where untrusted users can access client-management inputs. The CVE record's structured affected fields are n/a, so inventory confirmation is required.
Exploitation context
The bundle does not indicate active exploitation, and KEV is false. The issue requires a user with low privileges to store content and a victim to view affected pages. Sources do not provide a vendor patch or named mitigation.
Researcher notes
Evidence is sparse. The CVE description names SCMS 1.0 and MAster.php, but structured affected metadata is n/a and the bundle provides no patch information. Avoid assuming broader product versions, exploit maturity, or remediation beyond checking upstream guidance and validating code behavior.
Mitigation direction
- Identify whether SCMS 1.0 is deployed in any environment.
- Check the project or vendor source for fixed releases or official guidance.
- Restrict access to SCMS administrative and client-management pages while assessing exposure.
- Apply output encoding and input validation if maintaining the application code.
- Review stored client records for unexpected HTML or script content.
Validation and detection
- Inventory systems for Sourcecodetester SCMS 1.0 deployments.
- Confirm whether MAster.php exists and handles user-controlled fields.
- Review vulnerable fields for stored untrusted markup without output encoding.
- Check application records for suspicious saved HTML or script content.
- Verify remediation by confirming stored text renders inertly, not as executable markup.
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-2021-43657 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://github.com/c0n5n3d/CVE-2021-43657/blob/main/Info.txtCVE reference
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.