CVE-2026-4103Network attack vector

Stored XSS via incomplete API-document sanitization

Published Sep 14, 2026 · Updated Sep 14, 2026

Stored XSS in WSO2 API Manager and API Control Plane affected releases allows remote authenticated users to execute JavaScript in portal users' browsers. The Publisher and Developer Portal HTMLRender components parse API-document HTML after applying an incomplete disallowed-tag filter rather than neutralizing unsafe markup. Execution occurs when affected documentation is rendered, allowing code to act with the viewing user's portal-session privileges.

CVSS severity6.4
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in WSO2 API Manager and API Control Plane affected releases allows remote authenticated users to execute JavaScript in portal users' browsers. The Publisher and Developer Portal HTMLRender components parse API-document HTML after applying an incomplete disallowed-tag filter rather than neutralizing unsafe markup. Execution occurs when affected documentation is rendered, allowing code to act with the viewing user's portal-session privileges.

The record

CVE
CVE-2026-4103
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
WSO2
Product
WSO2 API Control Plane
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.5.0 <4.5.0.55
  2. Affected versionversion=4.6.0 <4.6.0.19

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WSO2 · WSO2 API Control Planeversion=4.5.0 <4.5.0.55; version=4.6.0 <4.6.0.19
WSO2 · WSO2 API Managerversion=3.2.0 <3.2.0.470; version=3.2.1 <3.2.1.89; version=4.1.0 <4.1.0.254; version=4.2.0 <4.2.0.194; version=4.3.0 <4.3.0.105; version=4.4.0 <4.4.0.69; version=4.5.0 <4.5.0.54; version=4.6.0 <4.6.0.18

Published CVSS scores

6.4WSO2CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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