CVE-2026-128424
Description
A flaw was found in Kroxylicious. The ACL authorizer's rules-file parser unquotes matching /…/ regular-expression literals using the string unquoting rules, which strips every backslash escape. As a result, an allow rule such as matching /orders\.v1/ is compiled as the regex orders.v1, which also matches unintended names such as ordersXv1, and character classes such as \d and \w lose their special meaning. Allow rules written with regex escapes can therefore apply to more resources than the author intended. Depending on the ACL configuration, this may allow an authenticated Kafka client to access a resource (such as read or write a topic) that should have been denied.
Statement
Rated Moderate because exploitation requires a deployment whose ACL rules use matching literals with single-backslash escapes, and an authenticated client whose principal matches a broadened rule. The impact is limited to the permissions already expressible in the affected allow rules; there is no authentication bypass or availability impact.
Mitigation
Until a fixed release is available, write regex escapes with doubled backslashes (for example `/orders\\.v1/`), audit existing `matching` rules for unintended matches, and prefer exact or `like` predicates where regex matching is not required.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker could bypass intended access restrictions to read sensitive data, either by reading the data directly from a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity
Technical Impact: Modify Application Data; Modify Files or Directories
An attacker could bypass intended access restrictions to modify sensitive data, either by writing the data directly to a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism
An attacker could bypass intended access restrictions to gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Confidentiality,Integrity,Availability
Technical Impact: Execute Unauthorized Code or Commands
An attacker could use elevated privileges to execute unauthorized commands or code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An attacker could gain unauthorized access to resources on the system and excessively consume those resources, leading to a denial of service.
Acknowledgements
Red Hat would like to thank Carles Arnal (IBM) for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
