A moderate out-of-bounds write vulnerability in Apache Hadoop’s HDFS native client that could allow attackers to trigger system crashes or cause data corruption in production environments.Â
The flaw, identified as CVE-2025-27821, affects the native HDFS client’s URI parser and has been assigned moderate severity by Apache.
The vulnerability was discovered and reported by security researcher BUI Ngoc Tan.
Apache Hadoop, a widely used distributed storage and processing framework, is fundamental to big data operations across thousands of enterprises.
The HDFS (Hadoop Distributed File System) native client is commonly deployed in data pipelines and cluster management configurations.
An out-of-bounds write condition in the URI parser allows untrusted input to write data beyond allocated memory boundaries, potentially corrupting system memory or causing denial-of-service conditions.
Vulnerable Versions and Mitigation
The vulnerability impacts Apache Hadoop HDFS native client versions 3.2.0 through 3.4.1. Systems running version 3.4.2 or later are not affected.
Apache recommends that all affected organizations immediately prioritize upgrading to version 3.4.2, which contains the necessary patches to remediate the vulnerability. The issue is being tracked under JIRA ticket HDFS-17754.
| Field | Details |
|---|---|
| CVE ID​ | CVE-2025-27821 |
| Component​ | Apache Hadoop HDFS Native Client (org.apache.hadoop:hadoop-hdfs-native-client) |
| Vulnerability Type​ | Out-of-Bounds Write in URI Parser |
| Severity​ | Moderate |
The out-of-bounds write occurs during URI parsing, suggesting the vulnerability could be exploited by providing maliciously crafted URIs to HDFS clients.
Successful exploitation could lead to memory corruption, uncontrolled system behavior, data loss, or complete system unavailability.
Organizations storing sensitive data on HDFS clusters face particular risk if the vulnerability is exploited in production environments.
Organizations should immediately assess their Hadoop deployment versions and prioritize upgrading to patched releases.
System administrators should monitor HDFS logs for suspicious URI patterns and consider implementing network-level access controls to restrict HDFS client connections to trusted sources.
Patch management procedures should treat this vulnerability as a priority given its potential for system-level impact.
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