CVE-2026-40164
published 2026-04-14CVE-2026-40164: jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed…
PriorityP343high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.37%
28.4th percentile
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.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| jqlang | jq | < 0c7d133c3c7e37c00b6d46b658a02244fdd3c784 | 0c7d133c3c7e37c00b6d46b658a02244fdd3c784 |
| ubuntu | jq | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_ubuntu8.2HIGH
vendor_redhat7.5HIGH
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Ubuntu
jq regression
vendor_ubuntu·2026-05-21·CVSS 7.5
CVE-2026-40164 [HIGH] jq regression
Title: jq regression
Summary: USN-8202-1 introduced a regression in jq
USN-8202-1 fixed vulnerabilities in jq. The update caused a regression
for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
It was discovered that jq did not correctly handle certain string
concatenations. An attacker could possibly use this issue to cause a denial
of service or execute arbitrary code. This issue was addressed in Ubuntu
16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu
24.04 LTS and Ubuntu 25.10. (CVE-2026-32316)
It was discovered that jq did not correctly handle recursion in certain
circumstances. An attacker could possibly use this issue to cause a denial
of service. (CVE-2026-33947)
It was
Ubuntu
jq vulnerabilities
vendor_ubuntu·2026-04-28·CVSS 8.2
CVE-2026-33948 [HIGH] jq vulnerabilities
Title: jq vulnerabilities
Summary: Several security issues were fixed in jq.
USN-8202-1 fixed vulnerabilities in jq. This update provides the
corresponding update to Ubuntu 26.04 LTS.
Original advisory details:
It was discovered that jq did not correctly handle certain string
concatenations. An attacker could possibly use this issue to cause a
denial of service or execute arbitrary code. (CVE-2026-32316)
It was discovered that jq did not correctly handle recursion in certain
circumstances. An attacker could possibly use this issue to cause a denial
of service. (CVE-2026-33947)
It was discovered that jq did not correctly handle improperly terminated
strings. An attacker could possibly use this issue to cause a denial of
service or execute arbitrary code. (CVE-2026-33948)
It was disco
Ubuntu
jq vulnerabilities
vendor_ubuntu·2026-04-23·CVSS 8.2
CVE-2026-32316 [HIGH] jq vulnerabilities
Title: jq vulnerabilities
Summary: Several security issues were fixed in jq.
It was discovered that jq did not correctly handle certain string
concatenations. An attacker could possibly use this issue to cause a denial
of service or execute arbitrary code. This issue was addressed in Ubuntu
16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu
24.04 LTS and Ubuntu 25.10. (CVE-2026-32316)
It was discovered that jq did not correctly handle recursion in certain
circumstances. An attacker could possibly use this issue to cause a denial
of service. (CVE-2026-33947)
It was discovered that jq did not correctly handle improperly terminated
strings. An attacker could possibly use this issue to cause a denial of
service or execute arbitrary code. This issue was addressed in Ubu
Red Hat
jq: jq: Denial of Service via crafted JSON object causing hash collisions
vendor_redhat·2026-04-13·CVSS 7.5
CVE-2026-40164 [HIGH] CWE-341 jq: jq: Denial of Service via crafted JSON object causing hash collisions
jq: jq: Denial of Service via crafted JSON object causing hash collisions
A flaw was found in jq, a command-line JSON processor. A remote attacker could exploit this vulnerability by providing a specially crafted JSON object. This object leverages a weakness in jq's hashing algorithm, which uses a hardcoded, publicly known seed. By crafting the JSON object to cause hash collisions, an attacker can degrade the performance of JSON object hash table operations, leading to significant CPU exhaustion and a denial of service (DoS) for systems processing the malicious JSON data.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread insta
VulDB
jqlang jq JSON Object Hash Table weak hash (GHSA-wwj8-gxm6-jc29 / Nessus ID 307505)
vuldb·2026-04-20·CVSS 7.5
CVE-2026-40164 [HIGH] jqlang jq JSON Object Hash Table weak hash (GHSA-wwj8-gxm6-jc29 / Nessus ID 307505)
A vulnerability classified as problematic has been found in jqlang jq. This impacts an unknown function of the component JSON Object Hash Table Handler. This manipulation causes use of weak hash.
This vulnerability appears as CVE-2026-40164. The attack may be initiated remotely. There is no available exploit.
It is recommended to apply a patch to fix this issue.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions [fedora-all]
bugzilla·2026-04-14·CVSS 7.5
CVE-2026-40164 [HIGH] CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions [fedora-all]
CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions
bugzilla·2026-04-14·CVSS 7.5
CVE-2026-40164 [HIGH] CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions
CVE-2026-40164 jq: jq: Denial of Service via crafted JSON object causing hash collisions
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
https://github.com/jqlang/jq/commit/0c7d133c3c7e37c00b6d46b658a02244fdd3c784https://github.com/jqlang/jq/security/advisories/GHSA-wwj8-gxm6-jc29https://access.redhat.com/errata/RHSA-2026:16252https://access.redhat.com/errata/RHSA-2026:16692https://access.redhat.com/errata/RHSA-2026:16693https://access.redhat.com/errata/RHSA-2026:18040https://access.redhat.com/errata/RHSA-2026:18042https://access.redhat.com/errata/RHSA-2026:18043https://access.redhat.com/errata/RHSA-2026:18044https://access.redhat.com/errata/RHSA-2026:18045https://access.redhat.com/errata/RHSA-2026:18046https://access.redhat.com/errata/RHSA-2026:18047https://access.redhat.com/errata/RHSA-2026:18048https://access.redhat.com/errata/RHSA-2026:19151https://access.redhat.com/errata/RHSA-2026:19365https://access.redhat.com/errata/RHSA-2026:23233https://access.redhat.com/errata/RHSA-2026:23245https://access.redhat.com/errata/RHSA-2026:25044https://access.redhat.com/errata/RHSA-2026:25096https://access.redhat.com/errata/RHSA-2026:25181https://access.redhat.com/errata/RHSA-2026:26528https://access.redhat.com/errata/RHSA-2026:26542https://access.redhat.com/errata/RHSA-2026:30078https://access.redhat.com/errata/RHSA-2026:30087https://access.redhat.com/errata/RHSA-2026:30088https://access.redhat.com/errata/RHSA-2026:30089https://access.redhat.com/errata/RHSA-2026:8579https://access.redhat.com/security/cve/CVE-2026-40164https://bugzilla.redhat.com/show_bug.cgi?id=2458084https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40164.json
2026-04-14
Published