Red Hat Keycloak X.509 Client Certificate Authenticator information disclosure

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.9$5k-$25k0.46

Summaryinfo

A vulnerability, which was classified as problematic, was found in Red Hat Keycloak. This affects an unknown function of the component X.509 Client Certificate Authenticator. Executing a manipulation can lead to information disclosure. This vulnerability is registered as CVE-2026-103884. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as problematic was found in Red Hat Keycloak (affected version not known). This vulnerability affects some unknown functionality of the component X.509 Client Certificate Authenticator. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. CVE summarizes:

A flaw was found in the X.509 client certificate authenticator of Keycloak. When CRL Distribution Point checking is enabled, the server fails to properly validate the file paths provided in a client certificate. An attacker can provide a specially crafted certificate that causes the server to attempt to read sensitive files from the local system or exhaust memory by loading extremely large files, potentially leading to information disclosure or a system crash.

The advisory is available at access.redhat.com. This vulnerability was named CVE-2026-103884 since 10/01/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/01/2026). This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.9

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (redhat): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/01/2026 Advisory disclosed
10/01/2026 +0 days CVE reserved
10/01/2026 +0 days VulDB entry created
10/01/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: redhat.com

Advisory: access.redhat.com
Status: Not defined

CVE: CVE-2026-103884 (🔒)
GCVE (CVE): GCVE-0-2026-103884
GCVE (VulDB): GCVE-100-412750

Entryinfo

Created: 10/01/2026 19:42
Changes: 10/01/2026 19:42 (26), 10/01/2026 19:43 (34)
Complete: 🔍
Cache ID: 216::103

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