Security readout for executives and security teams
Plain-English summary
YiiCMS v1.0 has a cross-site scripting issue in its news function. An attacker with low privileges could place content that runs in another user’s browser if that user views it. The CVE is rated medium, with limited confidentiality and integrity impact and no availability impact stated.
Executive priority
Treat as a moderate-priority web application risk. It is not currently evidenced as exploited, but it can affect user trust and session security if YiiCMS v1.0 is exposed.
Technical view
The CVE maps to CWE-79 and CVSS 3.1 score 5.4: network reachable, low complexity, low privileges required, user interaction required, scope changed, low C/I impact, no A impact. The public description identifies YiiCMS v1.0 and the news function, but affected-product metadata and patch details are incomplete.
Likely exposure
Exposure is likely limited to organizations running YiiCMS v1.0, especially where untrusted or semi-trusted users can create or edit news content viewed by others.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. CVSS indicates exploitation requires low privileges and user interaction, consistent with stored or triggered XSS risk in a browser context.
Researcher notes
Evidence is sparse: the CVE names YiiCMS v1.0 and the news function, while the structured affected fields are n/a. No patch, exploit status, or detailed vulnerable parameter is provided in the bundle.
Mitigation direction
- Confirm whether any YiiCMS v1.0 instances exist in production or staging.
- Review the maintainer issue and vendor guidance for a fixed version or supported patch.
- Restrict news creation and editing to trusted users until remediated.
- Apply output encoding and input handling fixes through a maintained patch path.
- Consider compensating controls such as stricter content moderation and browser security headers.
Validation and detection
- Inventory web applications for YiiCMS v1.0 usage.
- Review roles allowed to access the news function.
- Check whether news content is safely rendered as text, not executable script.
- Review existing news entries for suspicious embedded active content.
- Validate remediation in staging before production rollout.
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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-21246 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/yongshengli/yiicms/issues/6CVE 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.