Two Incomplete Fixes for a Path Traversal Vulnerability in ONNX (CVE-2026-27489)
Some vulnerabilities are patched once and forgotten. Others keep coming back because each fix only addresses the symptom rather than the root cause. The path traversal vulnerability in onnx is a textbook example of the latter. It has now been patched three times across four years: CVE-2022-25882, CVE-2024-27318, and most recently CVE-2026-27489, which I discovered and reported. Each patch closed one door while leaving another open. This post walks through all three patches, explains exactly where each fell short, and uses them to illustrate the secure coding lessons every developer should learn when handling file paths. ...