Report: CVE-2026-40164 - jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed
CVE ID :CVE-2026-40164 Published : April 14, 2026, 12:16 a.m. | 1 hour, 39 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 Visit the link for more details, such as CVSS details, affected products, timeline, and more...