Security readout for executives and security teams
Plain-English summary
CVE-2021-40289 is a medium-severity cross-site scripting issue reported in mm-wki v0.2.1. If an affected wiki is used, an attacker may be able to make a user view malicious content that runs script in the user’s browser.
Executive priority
Treat as a moderate web application risk. Prioritize internet-facing or collaborative wiki deployments because exploitation requires user interaction but could affect user sessions or page integrity.
Technical view
The CVE maps to CWE-79 with CVSS 3.1 score 6.1. The vector indicates network access, low complexity, no privileges required, user interaction required, changed scope, low confidentiality impact, low integrity impact, and no availability impact.
Likely exposure
Exposure is most likely where mm-wki or the related mm-wiki project is deployed, especially if reachable by untrusted users. The CVE affected-product metadata is incomplete and lists vendor, product, and versions as n/a.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Evidence supports public disclosure through a GitHub issue, but not weaponized exploitation or broad campaign activity.
Researcher notes
The source bundle is sparse. It names mm-wki v0.2.1, while the reference is under phachon/mm-wiki, and structured affected metadata is n/a. Confirm exact product lineage, affected version, and fix status before broad remediation tracking.
Mitigation direction
- Confirm whether any deployed wiki matches mm-wki or mm-wiki v0.2.1.
- Review upstream project guidance for a fixed version or workaround.
- Restrict access to affected wiki instances while validating exposure.
- Apply standard output encoding and input handling if maintaining a fork.
Validation and detection
- Inventory wiki software names, forks, and deployed versions.
- Review the referenced GitHub issue for affected behavior and maintainer guidance.
- Check whether untrusted users can submit or edit rendered wiki content.
- Review application logs for unusual script-like content or related user reports.
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-2021-40289 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
- https://github.com/phachon/mm-wiki/issues/319CVE 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.