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Keycloak has Incorrect Behavior Order: Authorization Before Parsing and Canonicalization

Moderate severity GitHub Reviewed Published Jan 8, 2026 to the GitHub Advisory Database • Updated Mar 5, 2026

Package

maven org.keycloak:keycloak-parent (Maven)

Affected versions

<= 26.5.0

Patched versions

None

Description

A flaw was found in Keycloak. The Keycloak Authorization header parser is overly permissive regarding the formatting of the "Bearer" authentication scheme. It accepts non-standard characters (such as tabs) as separators and tolerates case variations that deviate from RFC 6750 specifications.

References

Published by the National Vulnerability Database Jan 8, 2026
Published to the GitHub Advisory Database Jan 8, 2026
Reviewed Jan 8, 2026
Last updated Mar 5, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(8th percentile)

Weaknesses

Incorrect Behavior Order: Authorization Before Parsing and Canonicalization

If a web server does not fully parse requested URLs before it examines them for authorization, it may be possible for an attacker to bypass authorization protection. Learn more on MITRE.

CVE ID

CVE-2026-0707

GHSA ID

GHSA-gv94-wp4h-vv8p

Source code

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