What’s Vulnerable › Vulnerabilities

CVE-2025-47436: Apache ORC: Potential Heap Buffer Overflow during C++ LZO Decompression

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-05-14 · updated 2026-06-17
• Weakness: CWE-122

Description

Heap-based Buffer Overflow vulnerability in Apache ORC. A vulnerability has been identified in the ORC C++ LZO decompression logic, where specially crafted malformed ORC files can cause the decompressor to allocate a 250-byte buffer but then attempts to copy 295 bytes into it. It causes memory corruption. This issue affects Apache ORC C++ library: through 1.8.8, from 1.9.0 through 1.9.5, from 2.0.0 through 2.0.4, from 2.1.0 through 2.1.1. Users are recommended to upgrade to version 1.8.9, 1.9.6, 2.0.5, and 2.1.2, which fix the issue.

Affected products

• Apache Software Foundation Apache ORC: before 1.8.9; from 1.9.0 before 1.9.6; from 2.0.0 before 2.0.5; from 2.1.0 before 2.1.2 — fixed in 1.8.9, 1.9.6, 2.0.5, 2.1.2

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache ORC 1.8.9, 1.9.6, 2.0.5, 2.1.2. Check the vendor advisory for mitigations.

References

• https://lists.apache.org/thread/kd6tlv8fs5jybmsgxr4vrkdxyc866wrn
• https://orc.apache.org/security/CVE-2025-47436/
• http://www.openwall.com/lists/oss-security/2025/05/13/4

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