CVE-2025-27817

Status: AnalyzedHigh (7.5)—

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.

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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.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Base score: 7.5

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 69%
Percentile among all scored CVEs: 99
Score date: 10/6/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access85 %
Primary impactT1005 Data from Local Systemcollection90 %
Secondary impactT1090.004 Domain Frontingcommand and control80 %

CVSS red con AV:N/PR:N/UI:N. CWE-918 (SSRF) en Kafka Client. Lectura arbitraria de archivos y variables de entorno (T1005) mediante configuración SASL OAUTHBEARER no validada (sasl.oauthbearer.token.endpoint.url). Además permite SSRF a URLs no intencionadas (T1090.004 proxy/SSRF).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability Scanning SSL/TLS Inspection Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic

Affected technologies (1)

Apache — Kafka

CWEs

CWE-918

References

Raw JSON (NVD)

Show

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      "value": "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. \n\nSince 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."
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      "value": "Se ha identificado una posible vulnerabilidad de lectura de archivos arbitrarios y SSRF en el cliente Apache Kafka. Los clientes Apache Kafka aceptan datos de configuración para establecer la conexión SASL/OAUTHBEARER con los brókeres, incluyendo \"sasl.oauthbearer.token.endpoint.url\" y \"sasl.oauthbearer.jwks.endpoint.url\". Apache Kafka permite a los clientes leer un archivo arbitrario y devolver el contenido en el registro de errores, o enviar solicitudes a una ubicación no deseada. En aplicaciones donde las configuraciones de los clientes Apache Kafka pueden ser especificadas por un tercero no confiable, los atacantes pueden usar las configuraciones \"sasl.oauthbearer.token.endpoint.url\" y \"sasl.oauthbearer.jwks.endpoint.url\" para leer contenido arbitrario del disco y las variables de entorno, o realizar solicitudes a una ubicación no deseada. En particular, esta falla puede utilizarse en Apache Kafka Connect para escalar desde el acceso a la API REST al acceso al sistema de archivos, entorno o URL, lo cual puede ser indeseable en ciertos entornos, incluidos los productos SaaS. A partir de Apache Kafka 3.9.1/4.0.0, hemos añadido una propiedad del sistema (\"-Dorg.apache.kafka.sasl.oauthbearer.allowed.urls\") para establecer las URL permitidas en la configuración SASL JAAS. En la versión 3.9.1, acepta todas las URL de forma predeterminada para garantizar la compatibilidad con versiones anteriores. Sin embargo, a partir de la versión 4.0.0, el valor predeterminado es una lista vacía y los usuarios deben configurar las URL permitidas explícitamente."
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  "lastModified": "2026-06-17T09:04:16.300",
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