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.
Published: 2026-04-13
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service via excessive CPU usage caused by hash collision exploitation
Action: Immediate Patch
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4599-1 jq security update
Debian DLA Debian DLA DLA-4662-1 jq security update
Ubuntu USN Ubuntu USN USN-8202-2 jq vulnerabilities
Ubuntu USN Ubuntu USN USN-8202-3 jq regression
Ubuntu USN Ubuntu USN USN-8202-1 jq vulnerabilities
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:16252 cve-icon
https://access.redhat.com/errata/RHSA-2026:16692 cve-icon
https://access.redhat.com/errata/RHSA-2026:16693 cve-icon
https://access.redhat.com/errata/RHSA-2026:18040 cve-icon
https://access.redhat.com/errata/RHSA-2026:18042 cve-icon
https://access.redhat.com/errata/RHSA-2026:18043 cve-icon
https://access.redhat.com/errata/RHSA-2026:18044 cve-icon
https://access.redhat.com/errata/RHSA-2026:18045 cve-icon
https://access.redhat.com/errata/RHSA-2026:18046 cve-icon
https://access.redhat.com/errata/RHSA-2026:18047 cve-icon
https://access.redhat.com/errata/RHSA-2026:18048 cve-icon
https://access.redhat.com/errata/RHSA-2026:19151 cve-icon
https://access.redhat.com/errata/RHSA-2026:19365 cve-icon
https://access.redhat.com/errata/RHSA-2026:23233 cve-icon
https://access.redhat.com/errata/RHSA-2026:23245 cve-icon
https://access.redhat.com/errata/RHSA-2026:25044 cve-icon
https://access.redhat.com/errata/RHSA-2026:25096 cve-icon
https://access.redhat.com/errata/RHSA-2026:25181 cve-icon
https://access.redhat.com/errata/RHSA-2026:26528 cve-icon
https://access.redhat.com/errata/RHSA-2026:26542 cve-icon
https://access.redhat.com/errata/RHSA-2026:28887 cve-icon
https://access.redhat.com/errata/RHSA-2026:30078 cve-icon
https://access.redhat.com/errata/RHSA-2026:30087 cve-icon
https://access.redhat.com/errata/RHSA-2026:30088 cve-icon
https://access.redhat.com/errata/RHSA-2026:30089 cve-icon
https://access.redhat.com/errata/RHSA-2026:34098 cve-icon
https://access.redhat.com/errata/RHSA-2026:8579 cve-icon
https://access.redhat.com/security/cve/CVE-2026-40164 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2458084 cve-icon
https://github.com/jqlang/jq/commit/0c7d133c3c7e37c00b6d46b658a02244fdd3c784 cve-icon cve-icon cve-icon
https://github.com/jqlang/jq/security/advisories/GHSA-wwj8-gxm6-jc29 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-40164 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40164.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-40164 cve-icon
History

Wed, 15 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-341
References
Metrics threat_severity

None

threat_severity

Important


Tue, 14 Apr 2026 22:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 14 Apr 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Jqlang
Jqlang jq
Vendors & Products Jqlang
Jqlang jq

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
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-15T01:01:26.746Z

Reserved: 2026-04-09T19:31:56.014Z

Link: CVE-2026-40164

cve-icon Vulnrichment

Updated: 2026-07-15T01:01:26.746Z

cve-icon NVD

Status : Deferred

Published: 2026-04-14T00:16:07.360

Modified: 2026-07-15T02:21:02.860

Link: CVE-2026-40164

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-13T23:40:12Z

Links: CVE-2026-40164 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-15T15:45:07Z

Weaknesses