Apache

CVE-2025-27817: Apache Kafka Client: Arbitrary file read and SSRF vulnerability

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 8 Apr 2026. It cites 1 public report, the first from 8 Apr 2026.

tracker.crowdsec.net

How likely is exploitation in the next 30 days?

68.8%

EPSS score, percentile 99.3 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

7.5 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

3.1.0 through 3.9.0

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

Apache Kafka Client: Arbitrary file read and SSRF vulnerability

A possible arbitrary file read and SSRF vulnerability has been identified in Apache Kafka Client. Apache Kafka Clients accept configuration data for setting the SASL/OAUTHBEARER connection with the brokers, including "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url". Apache Kafka allows clients to read an arbitrary file and return the content in the error log, or sending requests to an unintended location. In applications where Apache Kafka Clients configurations can be specified by an untrusted party, attackers may use the "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url" configuratin to read arbitrary contents of the disk and environment variables or make requests to an unintended location. In particular, this flaw may be used in Apache Kafka Connect to escalate from REST API access to filesystem/environment/URL access, which may be undesirable in certain environments, including SaaS products. Since Apache Kafka 3.9.1/4.0.0, we have added a system property ("-Dorg.apache.kafka.sasl.oauthbearer.allowed.urls") to set the allowed urls in SASL JAAS configuration. In 3.9.1, it accepts all urls by default for backward compatibility. However in 4.0.0 and newer, the default value is empty list and users have to set the allowed urls explicitly.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

kafka.apache.org (Vendor advisory)

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (1 product)

Apache Software Foundation Apache Kafka Client
Status	Versions
Affected	3.1.0 through 3.9.0

Versions not listed are: unaffected.

Source: CVE List, as of 30 Oct 2026. About the data.

Weakness

CWE-918

CWE-918: Server-Side Request Forgery (SSRF)

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

Date	Event
10 Jun 2025	CVE record published

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CVE-2026-34197: Apache ActiveMQ Improper Input Validation Vulnerability (added 16 Apr 2026)
CVE-2024-38475: Apache HTTP Server Improper Escaping of Output Vulnerability (added 1 May 2025)
CVE-2025-24813: Apache Tomcat Path Equivalence Vulnerability (added 1 Apr 2025)