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7.5
jq's JSON processing can be slowed down by malicious input
CVE-2026-40164
Summary
A security issue in jq's JSON processing could allow an attacker to cause a denial-of-service (slowdown) by submitting a large, specially crafted JSON file. This could impact systems that rely on jq, such as continuous integration and deployment pipelines, web services, and data processing scripts. Update to the latest version of jq to resolve this issue.
Original title
jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table ...
Original description
jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table operations, which allowed an attacker to precompute key collisions offline. By supplying a crafted JSON object (~100 KB) where all keys hashed to the same bucket, hash table lookups degraded from O(1) to O(n), turning any jq expression into an O(n²) operation and causing significant CPU exhaustion. This affected common jq use cases such as CI/CD pipelines, web services, and data processing scripts, and was far more practical to exploit than existing heap overflow issues since it required only a small payload. This issue has been patched in commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784.
nvd CVSS3.1
7.5
Vulnerability type
CWE-328
CWE-407
Published: 14 Apr 2026 · Updated: 14 Apr 2026 · First seen: 14 Apr 2026