Reflected XSS Vulnerability in Authentication Flow URL Handling in @dapperduckling/keycloak-connector-server

published 2024-11-25 23 mo ago modified 2026-06-17 4 mo ago also GHSA-w5rq-g9r6-vrcg , EUVD-2024-3387

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits: 0; none known

@dapperduckling/keycloak-connector-server is an opinionated series of libraries for Node.js applications and frontend clients to interface with keycloak. A Reflected Cross-Site Scripting (XSS) vulnerability was discovered in the authentication flow of the application. This issue arises due to improper sanitization of the URL parameters, allowing the URL bar's contents to be injected and reflected into the HTML page. An attacker could craft a malicious URL to execute arbitrary JavaScript in the browser of a victim who visits the link. Any application utilizing this authentication library is vulnerable. Users of the application are at risk if they can be lured into clicking on a crafted malicious link. The vulnerability has been patched in version 2.5.5 by ensuring proper sanitization and escaping of user input in the affected URL parameters. Users are strongly encouraged to upgrade. If upgrading is not immediately possible, users can implement the following workarounds: 1. Employ a Web Application Firewall (WAF) to block malicious requests containing suspicious URL parameters. or 2. Apply input validation and escaping directly within the application’s middleware or reverse proxy layer, specifically targeting the affected parameters.

Patch / fix

fixed in 2

npm @dapperduckling/keycloak-connector-server 2.5.5
cloud_native_computing_foundation keycloak-connector 2.5.5

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 23 mo ago (2024-11-26)

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
GitHub	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@dapperduckling/keycloak-connector-server	<2.5.5	2.5.5

Affected products

DapperDuckling keycloak-connector
cloud_native_computing_foundation keycloak-connector

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary