GHSA-rhgq-f8x5-j2jc CVE-2026-4633
Keycloak's identity-first login flow exposes user information
Low
Maven
- Severity
- 3.7 / 10
- Low · CVSS 3.1
- Exploit chance (EPSS)
- 0.42%
- Chance of exploitation in the next 30 days. Higher than 36.57% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-209 Generation of Error Message Containing Sensitive Information
- Fix
26.6.1- Upgrade org.keycloak:keycloak-services to this version or later
Description
A flaw was found in Keycloak. A remote attacker can exploit differential error messages during the identity-first login flow when Organizations are enabled. This vulnerability allows an attacker to determine the existence of users, leading to information disclosure through user enumeration.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.keycloak:keycloak-services | >= 26.5.0, < 26.6.1 |
26.6.1 |
| org.keycloak:keycloak-services | < 26.4.12 |
26.4.12 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.keycloak:keycloak-services Maven → 26.6.1
- maven
<dependency><groupId>org.keycloak</groupId><artifactId>keycloak-services</artifactId><version>26.6.1</version></dependency>- gradle
implementation("org.keycloak:keycloak-services:26.6.1")
Severity breakdown
CVSS 3.1 3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-209: Generation of Error Message Containing Sensitive Information
The product generates an error message that includes sensitive information about its environment, users, or associated data.
How to prevent it
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
- Implementation: Handle exceptions internally and do not display errors containing potentially sensitive information to a user.
- Implementation: Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
- Implementation, Build and Compilation: Debugging information should not make its way into a production release.
- Implementation, Build and Compilation: Debugging information should not make its way into a production release.
- System Configuration: Where available, configure the environment to use less verbose error messages. For example, in PHP, disable the display_errors setting during configuration, or at runtime using the error_reporting() function.
- System Configuration: Create default error pages or messages that do not leak any information.
References
Advisories
Packages
Other links
- github.com/keycloak/keycloak/issues/47619
- github.com/keycloak/keycloak/pull/47635
- github.com/keycloak/keycloak/commit/b137016cc6dcfd9f59b2aa2e6d73af8b0ebf7c6e
- github.com/keycloak/keycloak/commit/b4558a874fa79341404ae4d2d8f240f22bfed340
- access.redhat.com/errata/RHSA-2026:19596
- access.redhat.com/security/cve/CVE-2026-4633
- bugzilla.redhat.com/show_bug.cgi
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-v3f7-2p4r-mwfw Keycloak vulnerable to cross-site scripting (xss) via case-insensitive uri validation bypass | High | Also affects org.keycloak:keycloak-services |
| GHSA-9jrw-8xf7-xqhq Keycloak vulnerable to information disclosure through arbitrary filesystem path probing | Medium | Also affects org.keycloak:keycloak-services |
| GHSA-w3p3-7cjg-vgfw Keycloak allows unauthorized access to resources via uma permission ticket bypass | Medium | Also affects org.keycloak:keycloak-services |
| GHSA-f5p5-6xmx-p252 Keycloak vulnerable to authorization bypass via incorrect uri comparison | High | Also affects org.keycloak:keycloak-services |
| GHSA-r7rc-c989-86g6 Keycloak: Attacker can re-enable and take over disabled clients via registration access token | Medium | Also affects org.keycloak:keycloak-services |
| GHSA-4gv3-mc9p-5wqc Keycloak: Unauthenticated account takeover via reset-credentials flow bypass | Critical | Also affects org.keycloak:keycloak-services |
| GHSA-6g26-7cx5-mrrg Keycloak: Information disclosure due to user profile permission bypass | Low | Also affects org.keycloak:keycloak-services |
| GHSA-cpf7-j4cf-vqx4 Keycloak has an Out-of-bounds Read | Medium | Also affects org.keycloak:keycloak-services |
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