CVE-2024-56128 | Apache Kafka: SCRAM authentication vulnerable to replay attacks when used without encryption

Incorrect Implementation of Authentication Algorithm in Apache Kafka's SCRAM implementation. Issue Summary: Apache Kafka's implementation of the Salted Challenge Response Authentication Mechanism (SCRAM) did not fully adhere to the requirements of RFC 5802 [1]. Specifically, as per RFC 5802, the server must verify that the nonce sent by the client in the second message matches the nonce sent by the server in its first message. However, Kafka's SCRAM implementation did not perform this validation. Impact: This vulnerability is exploitable only when an attacker has plaintext access to the SCRAM authentication exchange. However, the usage of SCRAM over plaintext is strongly discouraged as it is considered an insecure practice [2]. Apache Kafka recommends deploying SCRAM exclusively with TLS encryption to protect SCRAM exchanges from interception [3]. Deployments using SCRAM with TLS are not affected by this issue. How to Detect If You Are Impacted: If your deployment uses SCRAM authentication over plaintext communication channels (without TLS encryption), you are likely impacted. To check if TLS is enabled, review your server.properties configuration file for listeners property. If you have SASL_PLAINTEXT in the listeners, then you are likely impacted. Fix Details: The issue has been addressed by introducing nonce verification in the final message of the SCRAM authentication exchange to ensure compliance with RFC 5802. Affected Versions: Apache Kafka versions 0.10.2.0 through 3.9.0, excluding the fixed versions below. Fixed Versions: 3.9.0 3.8.1 3.7.2 Users are advised to upgrade to 3.7.2 or later to mitigate this issue. Recommendations for Mitigation: Users unable to upgrade to the fixed versions can mitigate the issue by: - Using TLS with SCRAM Authentication: Always deploy SCRAM over TLS to encrypt authentication exchanges and protect against interception. - Considering Alternative Authentication Mechanisms: Evaluate alternative authentication mechanisms, such as PLAIN, Kerberos or OAuth with TLS, which provide additional layers of security.

Published: 2024-12-18 Last update: 2025-06-20 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2024-56128 is rated Low Risk (39.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.77%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-56128

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.54% 0.77% +0.22%
2 2026-05-09 0.39% 0.54% +0.15%
3 2026-04-02 0.39%

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-56128

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2024-56128

GitHub Security Advisory for CVE-2024-56128

GHSA-p7c9-8xx8-h74f · Severity: low · Ecosystem: maven — Apache Kafka's SCRAM implementation Incorrectly Implements Authentication Algorithm

OS Trackers for CVE-2024-56128

vendor priority summary link
redhat high https://access.redhat.com/security/cve/CVE-2024-56128

Affected software / configurations for CVE-2024-56128

Vendor Product Version Raw CPE
apache kafka >= 0.10.2.0, < 3.7.2 cpe:2.3:a:apache:kafka:*:*:*:*:*:*:*:*
apache kafka 3.8.0 cpe:2.3:a:apache:kafka:3.8.0:*:*:*:*:*:*:*

References for CVE-2024-56128

cvelogic Threat Intelligence