VDB-364585 · CVE-2026-8830 · EUVD-2026-30841

Keycloak on Red Hat processAction client-side authentication

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.
4.3	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Keycloak on Red Hat. Affected by this issue is the function processAction. This manipulation causes use of client-side authentication. This vulnerability is registered as CVE-2026-8830. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability has been found in Keycloak on Red Hat (the affected version is unknown) and classified as problematic. Affected by this vulnerability is the function processAction. The manipulation with an unknown input leads to a use of client-side authentication vulnerability. The CWE definition for the vulnerability is CWE-603. A client/server product performs authentication within client code but not in server code, allowing server-side authentication to be bypassed via a modified client that omits the authentication check. As an impact it is known to affect integrity. The summary by CVE is:

A flaw was found in Keycloak. An authenticated user can bypass configured WebAuthn policies during credential registration by manipulating client-side JavaScript. This occurs because the server-side processAction() fails to validate that the newly created credential's parameters, such as public key algorithms, match the realm's configured WebAuthn policies. This could lead to the creation of credentials that do not adhere to administrative security requirements, potentially weakening the overall security posture of the system by allowing non-compliant authentication methods.

The advisory is shared at access.redhat.com. This vulnerability is known as CVE-2026-8830 since 05/18/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/19/2026).

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

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-30841). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Keycloak

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (redhat): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Use of client-side authentication
CWE: CWE-603 / CWE-602
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

05/18/2026 CVE reserved
05/19/2026 +1 days Advisory disclosed
05/19/2026 +0 days VulDB entry created
05/19/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: access.redhat.com
Status: Confirmed

CVE: CVE-2026-8830 (🔒)
GCVE (CVE): GCVE-0-2026-8830
GCVE (VulDB): GCVE-100-364585
EUVD: 🔒

Entryinfo

Created: 05/19/2026 08:29
Updated: 05/19/2026 12:21
Changes: 05/19/2026 08:29 (60), 05/19/2026 12:21 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.