CVE-2026-18217

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 60/100
Published: 2026-07-31 Modified: 2026-11-06 First seen: 2026-11-06 Status: active

Attack Surface

Network Low Complexity No Auth Scope Change

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Required
S: Changed
C: None
I: Low
A: None

Description

A flaw was found in the SAML protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs when Keycloak handles SAML authentication requests using the HTTP-Redirect binding. If a client is configured with a wildcard redirect URL, an attacker can craft a request that includes malicious parameters. When a user authenticates, Keycloak appends its legitimate response to the attacker's parameters. This can cause some service providers to process the attacker's data instead of the real login information, potentially leading to a user being logged into the wrong account.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
redhat build_of_keycloak -

References & Advisories (6)

https://access.redhat.com/errata/RHSA-2026:95760
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95761
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95759
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95762
vendor-advisory x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2508311
issue-tracking x_refsource_REDHAT

Bug Bounty Relevance

60 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

4.7 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N

EPSS — Exploitation Probability

0.52%
Raw Score 0.005230
Percentile 45.0%
Date 2026-11-13

EPSS Trend

2026-11-13
0.00523
2026-11-12
0.00523
2026-11-10
0.00523
2026-11-09
0.00523
2026-11-08
0.00523
2026-11-07
0.00523
2026-11-06
0.00364
2026-11-05
0.00364

Intelligence Sources

mitre ref →
nvd ref →