js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases
Priority LOW 30CWE-407Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 5 fixed, 50 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-407.
Summary
js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00415 36th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial js-yaml (nodeca): 4.2.0, 3.15.0js-yaml (npm): 4.2.0, 3.15.0Red Hat: 8 advisoriesRed Hat: 5 fixed, 50 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| nodeca | js-yaml | 4.0.0 to before 4.2.0; before 3.15.0 | 4.2.0, 3.15.0 | Patch available | CNA |
| — | js-yaml (npm) | 4.0.0 to before 4.2.0 | 4.2.0 | Patch available | GHSA-h67p-54hq-rp68 |
| — | js-yaml (npm) | before 3.15.0 | 3.15.0 | Patch available | GHSA-h67p-54hq-rp68 |
- js-yaml Vendornodeca Affected 4.0.0 to before 4.2.0; before 3.15.0 Fixed in 4.2.0, 3.15.0 Patch available CNA
- js-yaml (npm) Vendor— Affected 4.0.0 to before 4.2.0 Fixed in 4.2.0 Patch available GHSA-h67p-54hq-rp68
- js-yaml (npm) Vendor— Affected before 3.15.0 Fixed in 3.15.0 Patch available GHSA-h67p-54hq-rp68
Remediation
- Fix · CNA js-yaml (nodeca) Fixed in 4.2.0, 3.15.0
- Fix · GHSA-h67p-54hq-rp68 js-yaml (npm) Fixed in 4.2.0 Advisory →
- Fix · GHSA-h67p-54hq-rp68 js-yaml (npm) Fixed in 3.15.0 Advisory →
Red Hat 8 advisories
- RHSA-2026:84734 Released 2026-10-19 · Red Hat rating CriticalRHOAI 3.4.5 - Red Hat OpenShift AI
- Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-ai-gateway-payload-processing-rhel9, registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-autorag-rhel9 +47
- RHSA-2026:73987 Released 2026-09-30 · Red Hat rating CriticalRHOAI 3.3.7 - Red Hat OpenShift AI
- Red Hat OpenShift AI 3.3 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9, registry.redhat.io/rhoai/odh-data-science-pipelines-argo-argoexec-rhel9 +47
- RHSA-2026:65126 Released 2026-09-08 · Red Hat rating ImportantRHOAI 2.25.11 - Red Hat OpenShift AI
- Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-caikit-tgis-serving-rhel9, registry.redhat.io/rhoai/odh-dashboard-rhel9 +47
Show 5 more Red Hat advisories
- RHSA-2026:60520 Released 2026-08-27 · Red Hat rating CriticalRHOAI 3.4.4 - Red Hat OpenShift AI
- Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-autorag-rhel9, registry.redhat.io/rhoai/odh-built-in-detector-rhel9 +47
- RHSA-2026:56431 Released 2026-08-18 · Red Hat rating ImportantRed Hat OpenShift Data Foundation 4.18.27 security, enhancement & bug fix update
- Red Hat Openshift Data Foundation 4.18 registry.redhat.io/odf4/cephcsi-rhel9, registry.redhat.io/odf4/cephcsi-rhel9-operator, registry.redhat.io/odf4/mcg-core-rhel9 +16
- RHSA-2026:38236 Released 2026-07-11 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images nodejs24-1:24.18.0-0.3.hum1@aarch64, nodejs24-1:24.18.0-0.3.hum1@src, nodejs24-1:24.18.0-0.3.hum1@x86_64 +16
- RHSA-2026:37534 Released 2026-07-10 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images nodejs25-1:25.9.0-1.3.hum1@aarch64, nodejs25-1:25.9.0-1.3.hum1@src, nodejs25-1:25.9.0-1.3.hum1@x86_64 +16
- RHSA-2026:33866 Released 2026-06-30 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images nodejs26-1:26.4.0-1.3.hum1@aarch64, nodejs26-1:26.4.0-1.3.hum1@src, nodejs26-1:26.4.0-1.3.hum1@x86_64 +16
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Cryostat 4 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Network Observability Operator | Affected | No fix yet: Fix deferred |
| Node HealthCheck Operator | Affected | No fix yet: Fix deferred |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| OpenShift Pipelines | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 2 | Affected | No fix yet: Fix deferred |
| OpenShift Service Mesh 3 | Affected | No fix yet: Fix deferred |
| Red Hat 3scale API Management Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat AMQ Broker 7 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Security 4 | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Build of Keycloak | Affected | No fix yet: Fix deferred |
| Red Hat Build of Podman Desktop | Affected | No fix yet: Fix deferred |
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
| Red Hat Connectivity Link 1 | Affected | No fix yet: Fix deferred |
| Red Hat Data Grid 8 | Affected | No fix yet: Fix deferred |
| Red Hat Developer Hub 1 | Affected | No fix yet: Fix deferred |
| Red Hat Directory Server 11 | Affected | No fix yet: Fix deferred |
| Red Hat Directory Server 12 | Affected | No fix yet: Fix deferred |
| Red Hat Discovery 2 | Affected | No fix yet: Fix deferred |
| Red Hat Edge Manager 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix planned: Will not fix |
| Red Hat Fuse 7 | Affected | No fix yet: Fix deferred |
| Red Hat Hardened Images | Affected | No fix planned: Will not fix |
| Red Hat JBoss Enterprise Application Platform 7 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform 8 | Affected | No fix yet: Fix deferred |
| Red Hat JBoss Enterprise Application Platform Expansion Pack | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift GitOps | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Virtualization 4 | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Single Sign-On 7 | Affected | No fix yet: Fix deferred |
| Red Hat Trusted Artifact Signer | Affected | No fix yet: Fix deferred |
| Red Hat Trusted Profile Analyzer | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel - HawtIO 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apache Camel for Spring Boot 4 | Affected | No fix yet: Fix deferred |
| Red Hat build of Apicurio Registry 3 | Affected | No fix yet: Fix deferred |
| Self-service automation portal 2 | Affected | No fix yet: Fix deferred |
| streams for Apache Kafka 2 | Affected | No fix yet: Fix deferred |
| streams for Apache Kafka 3 | Affected | No fix yet: Fix deferred |
| Red Hat Hardened Images | Fixed | RHSA-2026:33866, RHSA-2026:37534, RHSA-2026:38236 |
| Red Hat OpenShift AI 2.25 | Fixed | RHSA-2026:65126 |
| Red Hat OpenShift AI 3.3 | Fixed | RHSA-2026:73987 |
| Red Hat OpenShift AI 3.4 | Fixed | RHSA-2026:60520, RHSA-2026:84734 |
| Red Hat Openshift Data Foundation 4.18 | Fixed | RHSA-2026:56431 |
Not affected: 13 products
- Gatekeeper 3
- Red Hat Directory Server 13
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images
- Red Hat OpenShift AI 2.25
- Red Hat OpenShift AI 3.3
- Red Hat OpenShift AI 3.4
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Dev Spaces
- Red Hat Openshift Data Foundation 4.18
- Red Hat Satellite 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53550
- 2026-10-03 Alias added: GHSA-h67p-54hq-rp68
- 2026-10-07 Fix available: RHSA-2026:73987 · Red Hat
- 2026-10-20 Fix available: RHSA-2026:84734 · Red Hat
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
More nodeca Js-yaml vulnerabilities
- TI-2026-42685 js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing CVSS 3.1HIGH 7.5
- TI-2026-42684 js-yaml: YAML merge-key chains can force quadratic CPU consumption CVSS 3.1HIGH 7.5
- TI-2026-42683 js-yaml: YAML merge-key chains can force quadratic CPU consumption CVSS 3.1HIGH 7.5
- TI-2013-04085 The JS-YAML module before 2.0.5 for Node.js parses input without properly considering the… CVSS 2.0MEDIUM 6.8
- TI-2025-40064 js-yaml has prototype pollution in merge (<<) CVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-53550 · CVE Program
- CVE-2026-53550 · NVD
- FIRST EPSS
- GHSA-h67p-54hq-rp68 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-53550 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences