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CVE-2021-38153

Timing Attack Vulnerability for Apache Kafka Connect and Clients

5.9 MediumFix available

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
None
Availability
None

Exploit likelihood

6.20%Up 5.8 points since Sep 23, 2021
90%50%10%1%

What each source reports

NVD Score used 5.9

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
CVE-2021-38153
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:P/I:N/A:N
Weakness
CWE-203
Updated
2026-11-02
CVE List No score

Timing Attack Vulnerability for Apache Kafka Connect and Clients

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
CVE-2021-38153
Weakness
CWE-203
Updated
2026-11-02
EUVDEUVD-2021-1963 No score

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
EUVD-2021-1963
Updated
2026-11-03
GitHub AdvisoriesGHSA-3j6g-hxx5-3q26 5.9

Observable Discrepancy in Apache Kafka

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
GHSA-3j6g-hxx5-3q26
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-203
Updated
2026-11-02
OSV 5.9

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
CVE-2021-38153
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVGHSA-3j6g-hxx5-3q26 5.9

Observable Discrepancy in Apache Kafka

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
GHSA-3j6g-hxx5-3q26
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-203
Updated
2026-11-02
OSVUBUNTU-CVE-2021-38153 5.9

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
UBUNTU-CVE-2021-38153
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVBIT-kafka-2021-38153 No score

Timing Attack Vulnerability for Apache Kafka Connect and Clients

Some components in Apache Kafka use Arrays.equals to validate a password or key, which is vulnerable to timing attacks that make brute force attacks for such credentials more likely to be successful. Users should upgrade to 2.8.1 or higher, or 3.0.0 or higher where this vulnerability has been fixed. The affected versions include Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.5.0, 2.5.1, 2.6.0, 2.6.1, 2.6.2, 2.7.0, 2.7.1, and 2.8.0.

Record
BIT-kafka-2021-38153
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
org.apache.kafka:kafka_2.11
Maven
2.0.0 to 2.4.1 None known
org.apache.kafka:kafka_2.12
Maven
2.0.0 up to 2.6.3
2.6.3
org.apache.kafka:kafka_2.12
Maven
2.7.0 up to 2.7.2
2.7.2
org.apache.kafka:kafka_2.12
Maven
2.8.0 to 2.8.0
2.8.1
org.apache.kafka:kafka_2.13
Maven
2.4.0 up to 2.6.3
2.6.3
org.apache.kafka:kafka_2.13
Maven
2.7.0 up to 2.7.2
2.7.2
org.apache.kafka:kafka_2.13
Maven
2.8.0 to 2.8.0
2.8.1
org.apache.kafka:kafka-clients
Maven
2.0.0 up to 2.6.3
2.6.3
org.apache.kafka:kafka-clients
Maven
2.7.0 up to 2.7.2
2.7.2
org.apache.kafka:kafka-clients
Maven
2.8.0 to 2.8.0
2.8.1
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Affected packages
PackageAffectedFixed
kafka
Bitnami
2.0.0 up to 2.6.3, 2.7.0 up to 2.7.2, 2.8.0 up to 2.8.1
2.6.32.7.22.8.1
org.apache.kafka:kafka_2.11
Maven
2.0.0 to 2.4.1, plus listed versions
2.0.12.1.02.1.12.2.02.2.1
Show 4 moreShow less
2.2.22.3.02.3.12.4.0
None known
org.apache.kafka:kafka_2.12
Maven
2.0.0 up to 2.6.3, plus listed versions
2.0.12.1.02.1.12.2.02.2.1
Show 10 moreShow less
2.2.22.3.02.3.12.4.02.4.12.5.02.5.12.6.02.6.12.6.2
2.6.3
org.apache.kafka:kafka_2.12
Maven
2.7.0 up to 2.7.2, plus listed versions
2.7.1
2.7.2
org.apache.kafka:kafka_2.12
Maven
2.8.0 up to 2.8.1
2.8.1
org.apache.kafka:kafka_2.13
Maven
2.4.0 up to 2.6.3, plus listed versions
2.4.12.5.02.5.12.6.02.6.12.6.2
2.6.3
org.apache.kafka:kafka_2.13
Maven
2.7.0 up to 2.7.2, plus listed versions
2.7.1
2.7.2
org.apache.kafka:kafka_2.13
Maven
2.8.0 up to 2.8.1
2.8.1
org.apache.kafka:kafka-clients
Maven
2.0.0 up to 2.6.3, plus listed versions
2.0.12.1.02.1.12.2.02.2.1
Show 10 moreShow less
2.2.22.3.02.3.12.4.02.4.12.5.02.5.12.6.02.6.12.6.2
2.6.3
org.apache.kafka:kafka-clients
Maven
2.7.0 up to 2.7.2, plus listed versions
2.7.1
2.7.2
org.apache.kafka:kafka-clients
Maven
2.8.0 up to 2.8.1
2.8.1
kafka
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
2.2.0u2-0ubuntu3.12.2.0u2-0ubuntu3.22.2.2u1-0ubuntu1+esm2
None known

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-38153 is a medium vulnerability (CVSS 5.9) in Apache Kafka, published September 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 6.20%, the 93rd percentile. Fixed in org.apache.kafka:kafka_2.12 2.6.3.

References

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