Skip to main content

Apache Kafka Connect EUVDEUVD-2026-112174

| CVE-2026-116593 MEDIUM
2026-10-28 apache GHSA-mf84-q3cw-6ch9
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach Kafka Connect REST API
  2. Exploit
    Craft validate request referencing config provider
  3. Execution
    Worker resolves secret to plaintext
  4. Impact
    Exfiltrate disclosed credentials

Vulnerability Assessment

Exploitation Conditions

Exploitation requires (1) network access to a Kafka Connect worker's REST API, specifically the /connector-plugins/{connector-type}/config/validate endpoint, and (2) at least one Configuration Provider installed and configured on that worker whose secret references the attacker can cause to be resolved. The Kafka Connect REST API has no authentication enabled by default, so in default deployments the endpoint is reachable without credentials. Limiting factors: deployments that place the REST API behind authentication, TLS client auth, or network segmentation reduce reachability, and the disclosure is bounded to secrets resolvable by the Configuration Providers actually configured on the worker. No fix exists other than upgrading to 4.2.2, 4.3.2, or 4.4.0 or above as stated by the vendor.

Impact

No CVSS vector, EPSS score, KEV listing, or PoC reference is supplied, so most quantitative exploitation signals are absent and cannot be contrasted. The one available priority signal is the vendor-sourced decision label 'this_month', indicating a moderate, non-emergency priority rather than urgent active-exploitation triage. Qualitatively the flaw is a serious information-disclosure issue: Apache Kafka Connect's REST validate endpoint can be abused to resolve and return in plaintext the very secrets that Configuration Providers are designed to keep hidden (database passwords, API keys, broker credentials). Real-world risk hinges on exposure of the Connect REST API - which ships without authentication by default - and on whether Configuration Providers are actually in use; where both hold, an attacker who can reach the endpoint can harvest high-value secrets with low effort. This is a genuine priority for exposed Connect clusters, but because the REST API is often network-restricted or authenticated in hardened deployments, blanket criticality should be tempered by actual exposure. Authentication requirements cannot be confirmed from the available data because no CVSS vector is provided.

Exploit ScenarioDerived

An attacker who can reach a Kafka Connect worker's REST API sends a request to the /connector-plugins/{connector-type}/config/validate endpoint containing references that a configured Configuration Provider will resolve, causing the worker to return the resolved secret values in plaintext in the validation response. No public exploit code or PoC reference is identified in the provided data. Because the Connect REST API is unauthenticated by default, exploitation is straightforward wherever the endpoint is network-reachable and at least one Configuration Provider is installed.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Oct 28, 2026

Kafka Connect workers leak plaintext secrets through the REST API's /connector-plugins/{connector-type}/config/validate endpoint, which resolves Configuration Provider variables and returns the resolved values in its response, so anyone who can reach the endpoint can read credentials that were meant to stay hidden until runtime. Deployments are affected from Kafka 2.4.0 up to but not including 4.2.2, and from 4.3.0 up to but not including 4.3.2; the vendor fixed the behaviour in 4.2.2, 4.3.2 and 4.4.0. The request path requires no credentials (the assessed CVSS vector is AV:N/AC:L/PR:N/UI:N, and the Connect REST API has no authentication enabled by default), though disclosure is bounded to secrets that the Configuration Providers actually configured on that worker can resolve; no public exploit code, CISA KEV listing, or EPSS score was identified at time of analysis.

RemediationAI

Upgrade Kafka Connect to 4.2.2, 4.3.2, or 4.4.0 or above; the vendor states these versions fix the issue and the independent assessment confirms no other fix is offered, so patching is the only complete remediation. The vendor advisory index is at https://kafka.apache.org/cve-list. For workers that cannot be upgraded immediately, reduce reachability of the REST API: front it with authentication, require TLS client authentication, or place the listener behind network segmentation so only trusted hosts can call it - the trade-off is that every Connect client, UI and automation tool must then carry credentials or route through the allowed network path, and misconfigured clients will fail to submit or validate connectors. Because disclosure is bounded to secrets the installed Configuration Providers can resolve, removing or restricting unnecessary providers on a worker shrinks what the endpoint can leak, at the cost of losing the secret-hiding capability those providers supply for the affected connectors. Note that these measures limit exposure only; they do not correct the underlying behaviour, which is why upgrading to 4.2.2, 4.3.2 or 4.4.0 or above remains the required action.

Affected VersionsENISA

Apache Kafka 2.4.0 <4.2.2
Apache Kafka 4.3.0 <4.3.2

Affected Packages

euvd apache_kafka fix: 4.2.2, 4.3.2

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Apache Kafka Connect exposes a REST API for managing connectors, and its /connector-plugins/{connector-type}/config/validate endpoint exists to check a submitted connector configuration before it is created or updated. Kafka Connect also supports Configuration Providers, a pluggable ConfigProvider mechanism that lets operators keep sensitive values (passwords, tokens, connection strings) out of connector configuration files by storing them externally and resolving them only at runtime. The flaw is that the validation path performs that variable resolution and then returns the resolved plaintext in the endpoint's response, so the very feature designed to hide secrets becomes a disclosure channel for any caller who can reach the API. Because the Connect REST API ships without authentication by default and the assessed vector rates the attack as network-reachable with no privileges and no user interaction (AV:N/AC:L/PR:N/UI:N, C:H/I:N/A:N), exposure is essentially a function of network reachability to the worker's REST listener. The supplied data assigns no CWE, so the root-cause class is best described from the behaviour itself: missing authorization and over-permissive response construction on a validation endpoint that resolves secrets. The CPE record is a product-wide wildcard for apache_software_foundation:apache_kafka and does not distinguish the Connect module from the broker, so version scoping must come from the EUVD ranges rather than the CPE. The precise implementation detail of how the resolved values are echoed back is not described in the available sources; what is confirmed is that resolution occurs server-side during validation and the plaintext is returned to the caller.

Know when Apache Kafka gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

Vendor (apache) PRIMARY MEDIUM
vuln.today AI 7.5 HIGH

Remotely reachable REST endpoint that is unauthenticated by default (AV:N/AC:L/PR:N/UI:N) disclosing sensitive secrets, so C:H with no integrity or availability impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (apache).

Lifecycle Timeline

2
Patch available
Oct 28, 2026 - 17:19 EUVD
CVE Published
Oct 28, 2026 - 16:46 cve.org
MEDIUM

DescriptionCVE.org

Apache Kafka Connect has the /connector-plugins/{connector-type}/config/validate endpoint on its REST API to validate connector configurations. Apache Kafka Connect also support Configuration Providers which enable to hide the values of sensitive configuration and only resolve them at runtime.

An attacker with access to the validate endpoint can use it to resolve and return plaintext values via any of the configuration providers installed on a Connect worker.

Users are recommended to upgrade to version 4.2.2, 4.3.2, 4.4.0 or above, which fix this issue.

Threat Intelligence Overview

Prevalence
High
widely deployed enterprise streaming platform; Connect is a common integration component
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS N/A
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

CVE-2026-33557 CRITICAL
9.1 Apr 20

Apache Kafka 4.1.0 and 4.1.1 accept forged JWT tokens without signature validation, allowing remote unauthenticated atta

CVE-2026-33558 MEDIUM
5.3 Apr 20

Apache Kafka's NetworkClient component logs entire request and response payloads at DEBUG level, exposing sensitive auth

CVE-2026-41115 MEDIUM
4.3 Jun 02

Improper authorization in Apache Kafka 4.0.0-4.3.0 arises from a discrepancy between the documented ACL requirement and

CVE-2026-114349 HIGH
Oct 28

Memory exhaustion in the Apache Kafka broker lets an authenticated principal holding Write permission on a topic submit

CVE-2026-112375 HIGH
Oct 28

Apache Kafka brokers that have an authorizer enabled will read a file or environment variable from the broker host and r

CVE-2026-115644 LOW
Oct 28

Authentication bypass in Apache Kafka Connect's isolated admin REST API allows unauthenticated network attackers to read

CVE-2026-111551 HIGH
Oct 28

Network-reachable, unauthenticated deserialization flaws in Apache Kafka’s clients library and Kafka Streams can force m

CVE-2026-111496 LOW
Oct 28

Kafka Streams can be stalled indefinitely by a single record whose timestamp is at or near Long.MAX_VALUE, causing an in

CVE-2026-111115 HIGH
Oct 28

Unauthenticated remote attackers can exhaust broker heap and trigger process-wide GC stalls on Apache Kafka by declaring

CVE-2026-111108 HIGH
Oct 28

Heap exhaustion in Apache Kafka allows remote attackers to crash brokers by sending requests that declare an array eleme

CVE-2026-111073 MEDIUM
Oct 28

Apache Kafka brokers can be driven into heap exhaustion by any authenticated client because the PushTelemetry (KIP-714)

CVE-2026-110985 HIGH
Oct 28

Apache Kafka brokers that run SASL/OAUTHBEARER with the default DefaultJwtValidator and leave sasl.oauthbearer.jwks.endp

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy