2.7

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-1518

CVE-2026-1518: Keycloak: blind server-side request forgery (ssrf) via ciba backchannel notification endpoint in keycloak

A flaw was found in Keycloak’s CIBA feature where insufficient validation of client-configured backchannel notification endpoints could allow blind server-side requests to internal services.

(GitHub Advisory)

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CVE-2026-1518

CVE-2026-1518:

2.7

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
org.keycloak:keycloak-parent	maven	<= 26.5.2

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability CVE-2026-1518 is a Server-Side Request Forgery (SSRF) in Keycloak's CIBA implementation. The root cause is the insufficient validation of the backchannel_client_notification_endpoint provided by a client. When a CIBA flow is initiated, Keycloak sends a POST request to this endpoint. Without proper validation, an attacker can set this endpoint to an internal address, causing Keycloak to make a request to an internal service.

Although no specific patch was found, the vulnerability description allows for a logical deduction of the vulnerable function. The Keycloak component responsible for sending CIBA backchannel notifications via HTTP is the HttpAuthenticationChannel class. A method within this class, likely named request or similar, would be responsible for creating and sending the HTTP request. This method would be the entry point for the SSRF attack, as it would consume the malicious URL. Therefore, org.keycloak.protocol.oidc.grants.ciba.channel.HttpAuthenticationChannel.request is identified as the vulnerable function. The confidence is medium as this is based on deduction from the vulnerability description rather than analysis of a specific code change.

Vulnerable functions

org.keycloak.protocol.oidc.grants.ciba.channel.HttpAuthenticationChannel.request

services/src/main/java/org/keycloak/protocol/oidc/grants/ciba/channel/HttpAuthenticationChannel.java

This function is responsible for sending backchannel notifications for CIBA. According to the vulnerability description, it takes a user-provided URL (backchannel_client_notification_endpoint) and makes a POST request to it without proper validation. This allows an attacker with sufficient privileges to specify an internal URL, leading to a Server-Side Request Forgery (SSRF) vulnerability. The function would be called when a CIBA authentication flow is initiated in 'ping' mode.

Vulnerability Intelligence
Miggo AI

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WAF Rule

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Reasoning

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