CVE-2025-47436: Apache ORC Buffer Overflow Vulnerability

CVE-2025-47436 Overview

CVE-2025-47436 is a heap-based buffer overflow vulnerability affecting the Apache ORC C++ library's LZO decompression logic. When processing specially crafted malformed ORC files, the decompressor incorrectly allocates a 250-byte buffer but then attempts to copy 295 bytes into it, causing memory corruption. This vulnerability affects multiple versions of Apache ORC across different release branches.

Critical Impact

Successful exploitation of this heap-based buffer overflow can lead to memory corruption, potentially enabling arbitrary code execution or denial of service when processing malicious ORC files.

Affected Products

• Apache ORC C++ library through version 1.8.8
• Apache ORC C++ library versions 1.9.0 through 1.9.5
• Apache ORC C++ library versions 2.0.0 through 2.0.4
• Apache ORC C++ library versions 2.1.0 through 2.1.1

Discovery Timeline

• May 14, 2025 - CVE-2025-47436 published to NVD
• July 14, 2025 - Last updated in NVD database

Technical Details for CVE-2025-47436

Vulnerability Analysis

This heap-based buffer overflow (CWE-122) occurs in the ORC C++ library's LZO decompression module. The vulnerability arises when the decompression logic processes malformed ORC files that have been specifically crafted to trigger an incorrect buffer size calculation. The decompressor allocates a 250-byte buffer based on metadata in the malformed file but subsequently attempts to write 295 bytes of decompressed data into this undersized buffer.

The 45-byte overflow corrupts adjacent heap memory, which can destabilize the application, lead to crashes, or potentially be leveraged by attackers to achieve code execution depending on the heap layout and application context. The local attack vector requires an attacker to deliver a malicious ORC file to a victim system where it will be processed by an application using the vulnerable Apache ORC library.

Root Cause

The root cause lies in insufficient validation of compressed data boundaries within the LZO decompression logic. The decompressor trusts metadata from the ORC file to determine buffer allocation sizes without adequately verifying that the actual decompressed output will fit within the allocated space. This missing bounds check allows crafted files to specify smaller buffer sizes than the actual decompressed data requires.

Attack Vector

Exploitation requires a local attack vector where an attacker must convince a user or automated system to process a maliciously crafted ORC file. The attack requires high privileges and active user interaction. Attack scenarios include:

• Delivering malicious ORC files via email attachments to data engineering teams
• Uploading crafted ORC files to data processing pipelines that automatically ingest ORC data
• Compromising data lakes or storage systems to inject malicious ORC files
• Supply chain attacks targeting shared datasets in ORC format

The vulnerability mechanism involves crafting an ORC file with manipulated LZO compression metadata. When the vulnerable library attempts to decompress the data, the undersized buffer allocation combined with the oversized write operation causes heap memory corruption.

Detection Methods for CVE-2025-47436

Indicators of Compromise

• Application crashes or unexpected termination when processing ORC files
• Heap corruption errors or memory allocation failures in ORC processing components
• Abnormal memory consumption patterns during ORC file decompression
• Segmentation faults in applications utilizing the Apache ORC C++ library

Detection Strategies

• Monitor for crash dumps containing stack traces involving ORC LZO decompression functions
• Implement file integrity monitoring on ORC file storage locations for unexpected modifications
• Deploy endpoint detection to identify applications loading vulnerable Apache ORC library versions
• Analyze application logs for repeated failures during ORC file processing operations

Monitoring Recommendations

• Enable heap memory monitoring for applications processing untrusted ORC files
• Configure crash reporting and analysis for ORC-dependent data processing pipelines
• Implement anomaly detection for ORC file sizes and compression ratios
• Monitor network traffic for ORC files originating from untrusted sources

How to Mitigate CVE-2025-47436

Immediate Actions Required

• Upgrade Apache ORC C++ library to patched versions immediately
• Audit systems to identify all applications using vulnerable Apache ORC library versions
• Restrict processing of ORC files from untrusted sources until patches are applied
• Implement input validation to reject ORC files with suspicious characteristics

Patch Information

Apache has released security patches addressing this vulnerability. Users should upgrade to the following fixed versions based on their current branch:

• Version 1.8.9 for the 1.8.x branch
• Version 1.9.6 for the 1.9.x branch
• Version 2.0.5 for the 2.0.x branch
• Version 2.1.2 for the 2.1.x branch

For detailed patch information, refer to the Apache CVE-2025-47436 Advisory and the Apache Mailing List Thread.

Workarounds

• Disable or bypass LZO compression for ORC files until patches can be applied
• Implement strict access controls to limit who can submit ORC files for processing
• Deploy sandbox environments for processing untrusted ORC data
• Consider alternative compression codecs (such as ZLIB or ZSTD) that are not affected by this vulnerability

# Configuration example - Verify installed Apache ORC version
# Check for vulnerable versions and plan upgrade path

# For applications using Maven, check dependency version:
mvn dependency:tree | grep orc

# For C++ applications, verify library version:
strings /path/to/liborc.so | grep -i version

# Example: Upgrade to patched version in Maven project
# Update pom.xml with fixed version:
# <dependency>
#   <groupId>org.apache.orc</groupId>
#   <artifactId>orc-core</artifactId>
#   <version>2.1.2</version>
# </dependency>