CVE-2026-40164 (GCVE-0-2026-40164)
Vulnerability from cvelistv5
Published
2026-04-13 23:40
Modified
2026-04-14 19:27
CWE
  • CWE-328 - Use of Weak Hash
  • CWE-407 - Inefficient Algorithmic Complexity
Summary
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.
Impacted products
Vendor Product Version
jqlang jq Version: < 0c7d133c3c7e37c00b6d46b658a02244fdd3c784
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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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