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Splunk Connect for Kafka EUVDEUVD-2026-62968

| CVE-2026-76403 HIGH
Improper Certificate Validation (CWE-295)
2026-08-19 cisco GHSA-xf48-ph6x-76rj
7.4
CVSS 3.1 · Vendor: cisco
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Attack ChainAIDerived

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

  1. Access
    Gain Layer-2 or routing access to connector network
  2. Delivery
    Redirect connector-to-HEC TLS traffic via MitM proxy
  3. Exploit
    Present forged TLS certificate to connector
  4. Execution
    Connector accepts certificate (validation skipped in Kerberos path)
  5. Persist
    Decrypt and read or modify event stream
  6. Impact
    Forward (optionally tampered) data to Splunk HEC

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V12 - Secure Communication Certificate validation
Exploitation Conditions

Exploitation requires two specific preconditions: (1) Kerberos authentication must be the configured authentication method for the connector's HEC connection - deployments using token-based or other HEC authentication methods are not affected by this code path defect; (2) the attacker must achieve a network man-in-the-middle position between the Kafka connector and the Splunk HEC endpoint, which requires either compromised network infrastructure, Layer 2 access to the same network segment, or the ability to manipulate routing. The CVSS AC:H vector reflects this positioning requirement. Exploitation is further limited to Splunk Connect for Kafka 2.2.x versions strictly below 2.2.7; upgraded instances are not affected. There is no user interaction required once the attacker is positioned, and no authentication against the target system is needed.

Impact

The CVSS 3.1 score of 7.4 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) reflects an accurate picture: network attack vector is correct since the connector communicates with HEC over a network path, but AC:H appropriately captures the requirement that the attacker must be physically or logically interposed in the network path (e.g., via ARP spoofing, rogue routing, or compromised network infrastructure). PR:N is correct because the attacker does not need credentials on the affected system - they exploit the passive certificate bypass. The dual high impact on confidentiality and integrity (C:H/I:H) is significant: an attacker can read all Splunk-bound event data (log exfiltration) and silently alter it (log tampering, a severe forensic and SIEM integrity concern). No EPSS score was provided in the input data, so quantitative exploitation probability cannot be stated. No public exploit code or POC has been identified, and the vulnerability is not listed in CISA KEV. The AC:H constraint substantially limits opportunistic exploitation - this is most plausible in targeted attacks against environments with known network access, not mass scanning campaigns. The additional prerequisite of Kerberos authentication being configured for HEC (non-default in many deployments) further reduces the realistic at-risk population.

Exploit ScenarioDerived

An attacker with access to a network segment between the Kafka connector host and the Splunk HEC endpoint performs ARP poisoning or BGP route injection to redirect connector-to-HEC traffic through an attacker-controlled proxy. Because the Kerberos code path skips certificate validation, the connector accepts the attacker's self-signed or forged certificate, allowing full decryption of the TLS stream. The attacker passively exfiltrates sensitive log and event data flowing into Splunk, or actively modifies log entries before forwarding them to HEC, corrupting the SIEM's visibility into security events. No public exploit code is available at time of analysis.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 19, 2026

Certificate validation bypass in Splunk Connect for Kafka below version 2.2.7 allows a network-positioned unauthenticated attacker to intercept and modify event data in transit to Splunk Enterprise's HTTP Event Collector when Kerberos authentication is configured. The Kerberos code path fails to apply the connector's configured TLS certificate validation options when constructing the HTTP client, effectively negating transport security despite HEC's TLS configuration. No active exploitation has been identified (not in CISA KEV), but the confidentiality and integrity impact on Splunk-ingested telemetry data is high.

RemediationAI

Upgrade Splunk Connect for Kafka to version 2.2.7 or later, which is the vendor-confirmed patched release per EUVD-2026-62968 and the Splunk advisory at https://advisory.splunk.com/advisories/SVD-2026-0808. Installation guidance is available at the Splunk documentation page for Splunk Connect for Kafka 2.2. As a compensating control for environments that cannot immediately patch, consider switching the HEC authentication method away from Kerberos to a method that does not trigger the vulnerable code path, while accepting the trade-off of reduced authentication strength in that configuration. Alternatively, restrict network routing so that only authorized, controlled hosts can reach the HEC endpoint from the Kafka connector, reducing the attacker's ability to achieve a man-in-the-middle position (though this does not fix the underlying certificate validation defect). Consult the Splunk security configurations documentation referenced in the advisory for additional hardening options.

Affected VersionsENISA

Splunk Connect for Kafka 2.2 <2.2.7

Affected Packages

euvd splunk_connect_for_kafka fix: 2.2.7

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

The root cause is CWE-295 (Improper Certificate Validation): the Kerberos authentication code path within Splunk Connect for Kafka constructs its HTTP client without applying the administrator-configured certificate validation options. This means TLS certificate checks are silently skipped for the connector-to-HEC channel when Kerberos is the selected auth mechanism, even though HEC uses HTTPS. An attacker with a network-path position can present an untrusted or forged TLS certificate that the connector will accept without complaint, enabling a classic man-in-the-middle (MitM) interception scenario. The affected component is identified by CPE cpe:2.3:a:splunk:splunk_connect_for_kafka:*:*:*:*:*:*:*:* and confirmed by EUVD-2026-62968 to affect the 2.2.x branch prior to 2.2.7. This is a design/implementation defect in the Kafka connector's security library integration, not a flaw in Splunk Enterprise or the Kerberos protocol itself.

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Severity by source

Vendor (cisco) PRIMARY 7.4 HIGH
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
vuln.today AI 7.4 HIGH

Network vector and PR:N are correct as attacker is passive MitM; AC:H reflects mandatory network-path positioning; no availability impact applies.

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

Primary rating from Vendor (cisco).

CVSS VectorVendor: cisco

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

Lifecycle Timeline

2
Patch available
Aug 19, 2026 - 22:04 EUVD
CVE Published
Aug 19, 2026 - 21:35 cve.org
HIGH 7.4

DescriptionCVE.org

In Splunk Connect for Kafka versions below 2.2.7, an unauthenticated user positioned in the network path could read or alter all relevant data sent from the connector when Kerberos authentication is used with Hypertext Transfer Protocol (HTTP) Event Collector in Splunk Enterprise. The vulnerability is possible because the Kerberos authentication path does not apply the configured certificate validation options when it builds the HTTP client. For more information see Install Splunk Connect for Kafka (https://help.splunk.com/en/data-management/integrate-data-with-add-ons/splunk-connect-for-kafka/2.2/install/install-splunk-connect-for-kafka), Security configurations for Splunk Connect for Kafka (https://help.splunk.com/en/splunk-enterprise/get-data-in/splunk-connect-for-kafka/2.2/configure/security-configurations-for-splunk-connect-for-kafka), and Set up and use HTTP Event Collector with configuration files (https://help.splunk.com/en/splunk-enterprise/get-data-in/get-started-with-getting-data-in/9.4/get-data-with-http-event-collector/set-up-and-use-http-event-collector-with-configuration-files) in the Splunk documentation.

Executive ViewAI

Why It Matters

Splunk Connect for Kafka versions below 2.2.7 allow unauthenticated network attackers to bypass certificate validation and intercept or modify telemetry data in transit to Splunk Enterprise's HTTP Event Collector. No public exploit has been identified at time of analysis, but the vulnerability poses high confidentiality and integrity risk to organizations whose security monitoring relies on this data pipeline. Affected systems must be prioritized for immediate patching, as data pipeline integrity is foundational to incident response and threat detection capabilities.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 91% exploitable
Prevalence
Low
specialized Kafka-to-Splunk integration connector, niche enterprise footprint
Data Quality
5 sources
Confidence: Medium

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 HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

37
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +37
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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

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