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.
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References
History
Tue, 14 Apr 2026 00:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed | |
| Weaknesses | CWE-328 CWE-407 |
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| Metrics |
cvssV3_1
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Subscriptions
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-04-13T23:40:12.693Z
Reserved: 2026-04-09T19:31:56.014Z
Link: CVE-2026-40164
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Status : Received
Published: 2026-04-14T00:16:07.360
Modified: 2026-04-14T00:16:07.360
Link: CVE-2026-40164
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OpenCVE Enrichment
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