CVE WatchJul 15, 2026

CVE-2026-40164

jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly

CVSS

7.5

High

EPSS

0.4%

p29

KEV

—

Exploit Today

0-100

Published: Apr 14, 2026 · Last modified: Jul 15, 2026 · CWE-328 · CWE-407 · CWE-341

EPSS · 30d

0.4%EPSS · 30 days0.4%

2026-06-302026-07-16

Technical 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.

Official references

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