CVE-2026-40164 - jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed

CVE-2026-40164 - jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed

https://cvefeed.io/rssfeed/latest.atom / Tue, 04/14/2026 - 04:01
CVE ID :CVE-2026-40164
Published : April 14, 2026, 12:16 a.m. | 54 minutes ago
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.
Severity: 7.5 | HIGH
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