VulnerabilityPublished 13 Nov 2026

CVE-2026-128424: Kroxylicious · Incorrect Authorization

Source GCVE Database

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Authoritative record:CVE-2026-128424· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium.

Data as of 13 Nov 2026, 10:58 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	5.3

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-655w-c5cf-wj5f

What to do

Affected software

Product	Affected	Fixed in
streams for Apache Kafka 3kroxylicious-authorizer-acl	Affected–	Fixed in–

AI-suggested

Until a fixed Kroxylicious release is available, write regex escapes in ACL rules with doubled backslashes (e.g., /orders\\.v1/). Audit existing matching rules for unintended matches and prefer exact or 'like' predicates where regex matching is not required.

Description

A flaw in Kroxylicious's ACL authorizer causes the rules-file parser to improperly unquote regex literals, stripping backslash escapes. This leads to regex rules matching more resources than intended, potentially allowing authenticated Kafka clients to access or modify topics they should not. The issue affects ACL configurations using regex escapes with single backslashes. There is no authentication bypass or availability impact. Mitigation involves doubling backslashes in regex escapes and auditing ACL rules until a fixed release is available.

Impact

An attacker with authenticated Kafka client access may gain unintended read or write permissions to Kafka resources due to overly broad ACL regex matching. This can lead to unauthorized access to sensitive data or modification of topics. There is no impact on authentication or service availability. The confidentiality impact is rated high, while integrity and availability impacts are none.

Summary

The ACL authorizer in Kroxylicious improperly unquotes regular-expression literals in ACL rules by applying string unquoting rules that remove all backslash escapes. For example, a rule written as matching /orders\.v1/ is compiled as the regex orders.v1, which matches unintended resource names like ordersXv1. Similarly, character classes such as \d and \w lose their special meaning. This broadens the scope of allow rules, potentially permitting authenticated Kafka clients to access or write to resources that should have been denied based on the intended ACL configuration. The impact is limited to permissions already expressible in the affected allow rules, with no authentication bypass or denial of service. Exploitation requires an ACL deployment using matching literals with single-backslash escapes and an authenticated client whose principal matches the broadened rule.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 10:58 UTC

WeaknessesCWE-863

Technical details

References

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