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NVD / CVE Program· CNA apache

CVE-2021-38153: Timing Attack Vulnerability for Apache Kafka Connect and Clients

Noroxi assessment

Priority: Monitor (action score 25/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 6.2% (FIRST EPSS); higher than 93.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: org.apache.kafka:kafka_2.12 (Maven) 2.6.3, 2.7.2, 2.8.1; org.apache.kafka:kafka_2.13 (Maven) 2.6.3, 2.7.2, 2.8.1; org.apache.kafka:kafka-clients (Maven) 2.6.3, 2.7.2, 2.8.1.
  • Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to org.apache.kafka:kafka_2.12 (Maven) 2.6.3, 2.7.2, 2.8.1; org.apache.kafka:kafka_2.13 (Maven) 2.6.3, 2.7.2, 2.8.1; org.apache.kafka:kafka-clients (Maven) 2.6.3, 2.7.2, 2.8.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
Sep 22, 2021
Updated
Jun 17, 2026
EPSS
6.2% · 93th percentile

Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 6.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-38153

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachekafka
quarkusquarkus
oraclecommunications brm - elastic charging engine
oraclecommunications cloud native core policy
oraclefinancial services analytical applications infrastructure
oraclefinancial services behavior detection platform
oraclefinancial services enterprise case management
oracleprimavera unifier

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache kafka2.7.0 and later · before 2.7.2
  • apache kafka2.0.0 and later · before 2.6.3
  • apache kafka2.8.0
  • oracle communications brm - elastic charging enginebefore 12.0.0.4.6
  • oracle communications brm - elastic charging engine12.0.0.5.0
  • oracle communications cloud native core policy1.15.0
  • oracle financial services analytical applications infrastructure8.0.6.0 and later · up to 8.0.9.0 inclusive
  • oracle financial services analytical applications infrastructure8.1.0.0.0 and later · up to 8.1.20 inclusive
  • oracle financial services behavior detection platform8.0.6.0.0 and later · up to 8.0.8.0 inclusive
  • oracle financial services behavior detection platform8.1.1.0
  • oracle financial services behavior detection platform8.1.1.1
  • oracle financial services behavior detection platform8.1.2.0
  • oracle financial services enterprise case management8.0.7.1
  • oracle financial services enterprise case management8.0.7.2
  • oracle financial services enterprise case management8.0.8.0
  • oracle financial services enterprise case management8.0.8.1
  • oracle financial services enterprise case management8.1.1.0
  • oracle financial services enterprise case management8.1.1.1
  • oracle primavera unifier18.8
  • oracle primavera unifier19.12

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Kafka

    • Apache Kafka 2.0.x and later · up to and including 2.0.1affected
    • Apache Kafka 2.1.x and later · up to and including 2.1.1affected
    • Apache Kafka 2.2.x and later · up to and including 2.2.2affected
    • Apache Kafka 2.3.x and later · up to and including 2.3.1affected
    • Apache Kafka 2.4.x and later · up to and including 2.4.1affected
    • Apache Kafka 2.5.x and later · up to and including 2.5.1affected
    • Apache Kafka 2.6.x and later · up to and including 2.6.2affected
    • Apache Kafka 2.7.x and later · up to and including 2.7.1affected
    • Apache Kafka 2.8.x and later · up to and including 2.8.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.apache.kafka:kafka_2.11from 2.0.0 · up to and including 2.4.1—
Mavenorg.apache.kafka:kafka_2.12from 2.0.0 · before 2.6.32.6.3
Mavenorg.apache.kafka:kafka_2.12from 2.7.0 · before 2.7.22.7.2
Mavenorg.apache.kafka:kafka_2.12from 2.8.0 · before 2.8.12.8.1
Mavenorg.apache.kafka:kafka_2.13from 2.4.0 · before 2.6.32.6.3
Mavenorg.apache.kafka:kafka_2.13from 2.7.0 · before 2.7.22.7.2
Mavenorg.apache.kafka:kafka_2.13from 2.8.0 · before 2.8.12.8.1
Mavenorg.apache.kafka:kafka-clientsfrom 2.0.0 · before 2.6.32.6.3
Mavenorg.apache.kafka:kafka-clientsfrom 2.7.0 · before 2.7.22.7.2
Mavenorg.apache.kafka:kafka-clientsfrom 2.8.0 · before 2.8.12.8.1

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-27817Apache Kafka Client: Arbitrary file read and SSRF vulnerability
    51Plan
  • CVE-2018-17196In Apache Kafka versions between 0.11.0.0 and 2.1.0, it is possible to manually craft a Produce request which bypasses transaction/idempoten
    37Monitor
  • CVE-2026-33557Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2018-1288Jul 26, 2018 · In Apache Kafka 0.9.0.0 to 0.9.0.1, 0.10.0.0 to 0.10.2.1, 0.11.0.0 to 0.11.0.2, and 1.0.0, authenticated Kafka users may perform action rese
    22Monitor
  • ← EarlierCVE-2019-12399Jan 14, 2020 · When Connect workers in Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, or 2.3.0 are configured with one or more config providers, an
    31Monitor
  • Later →CVE-2022-34917Sep 20, 2022 · Unauthenticated clients may cause OutOfMemoryError on Apache Kafka Brokers
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.apache.kafka:kafka_2.122.6.3Package registry (OSV)
Maven:org.apache.kafka:kafka_2.122.7.2Package registry (OSV)
Maven:org.apache.kafka:kafka_2.122.8.1Package registry (OSV)
Maven:org.apache.kafka:kafka_2.132.6.3Package registry (OSV)
Maven:org.apache.kafka:kafka_2.132.7.2Package registry (OSV)
Maven:org.apache.kafka:kafka_2.132.8.1Package registry (OSV)
Maven:org.apache.kafka:kafka-clients2.6.3Package registry (OSV)
Maven:org.apache.kafka:kafka-clients2.7.2Package registry (OSV)
Maven:org.apache.kafka:kafka-clients2.8.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-203 · Observable Discrepancy

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (10 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records