js-yaml: YAML merge-key chains can force quadratic CPU consumption
Priority HIGH 72CWE-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 · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-407.
Summary
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in version 5.2.0.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00644 51st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed js-yaml (nodeca): 5.2.0js-yaml (npm): 5.2.0Red Hat: 9 advisories
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- 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 | 5.0.0 to before 5.2.0 | 5.2.0 | Patch available | CNA |
| — | js-yaml (npm) | 5.0.0 to before 5.2.0 | 5.2.0 | Patch available | GHSA-g796-fgmg-93mv |
- js-yaml Vendornodeca Affected 5.0.0 to before 5.2.0 Fixed in 5.2.0 Patch available CNA
- js-yaml (npm) Vendor— Affected 5.0.0 to before 5.2.0 Fixed in 5.2.0 Patch available GHSA-g796-fgmg-93mv
Remediation
- Fix · CNA js-yaml (nodeca) Fixed in 5.2.0
- Fix · GHSA-g796-fgmg-93mv js-yaml (npm) Fixed in 5.2.0 Advisory →
Red Hat 9 advisories
- RHSA-2026:61783 Released 2026-08-31 · Red Hat rating ImportantA Subscription Management tool for finding and reporting Red Hat product usage
- Red Hat Discovery 2 registry.redhat.io/discovery/discovery-server-rhel9, registry.redhat.io/discovery/discovery-ui-rhel9
- RHSA-2026:35272 Released 2026-07-03 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images nodejs22-1:22.23.1-2.hum1@aarch64, nodejs22-1:22.23.1-2.hum1@src, nodejs22-1:22.23.1-2.hum1@x86_64 +14
- RHSA-2026:34975 Released 2026-07-02 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images cargo-1.96.1-1.hum1@aarch64, cargo-1.96.1-1.hum1@x86_64, clippy-1.96.1-1.hum1@aarch64 +36
Show 6 more Red Hat advisories
- RHSA-2026:34478 Released 2026-07-01 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images nodejs24-1:24.18.0-0.2.hum1@aarch64, nodejs24-1:24.18.0-0.2.hum1@src, nodejs24-1:24.18.0-0.2.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
- RHSA-2026:26994 Released 2026-06-18 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images dotnet-sdk-8.0-8.0.128-1.hum1@aarch64, dotnet-sdk-8.0-8.0.128-1.hum1@x86_64, dotnet-sdk-8.0-source-built-artifacts-8.0.128-1.hum1@aarch64 +6
- RHSA-2026:9455 Released 2026-04-21 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images nodejs20-20.20.2-1.hum1@aarch64, nodejs20-20.20.2-1.hum1@src, nodejs20-20.20.2-1.hum1@x86_64 +14
- RHSA-2026:7655 Released 2026-04-11 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images yarnpkg-1.22.22-18.1.hum1@aarch64, yarnpkg-1.22.22-18.1.hum1@src, yarnpkg-1.22.22-18.1.hum1@x86_64
- RHSA-2026:7378 Released 2026-04-10 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images nodejs25-25.9.0-1.1.hum1@aarch64, nodejs25-25.9.0-1.1.hum1@src, nodejs25-25.9.0-1.1.hum1@x86_64 +14
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Discovery 2 | Fixed | RHSA-2026:61783 |
| Red Hat Hardened Images | Fixed | RHSA-2026:26994, RHSA-2026:33866, RHSA-2026:34478, RHSA-2026:34975, RHSA-2026:35272, RHSA-2026:7378, RHSA-2026:7655, RHSA-2026:9455 |
Not affected: 53 products
- Cryostat 4
- Gatekeeper 3
- Migration Toolkit for Applications 8
- Migration Toolkit for Containers
- Multicluster Engine for Kubernetes
- Network Observability Operator
- Node HealthCheck Operator
- OpenShift Lightspeed
- OpenShift Pipelines
- OpenShift Service Mesh 3
- Red Hat 3scale API Management Platform 2
- Red Hat AMQ Broker 7
- Red Hat Advanced Cluster Management for Kubernetes 2
- Red Hat Advanced Cluster Security 4
- Red Hat Ansible Automation Platform 2
- Red Hat Build of Keycloak
- Red Hat Build of Podman Desktop
- Red Hat Ceph Storage 9
- Red Hat Connectivity Link 1
- Red Hat Data Grid 8
- Red Hat Developer Hub 1
- Red Hat Directory Server 11
- Red Hat Directory Server 12
- Red Hat Directory Server 13
- Red Hat Discovery 2
- Red Hat Edge Manager 1
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Enterprise Linux AI (RHEL AI) 3
- Red Hat Hardened Images
- Red Hat JBoss Enterprise Application Platform 7
- Red Hat JBoss Enterprise Application Platform 8
- Red Hat JBoss Enterprise Application Platform Expansion Pack
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat OpenShift Dev Spaces
- Red Hat OpenShift GitOps
- Red Hat OpenShift Virtualization 4
- Red Hat Openshift Data Foundation 4
- Red Hat Quay 3
- Red Hat Satellite 6
- Red Hat Single Sign-On 7
- Red Hat Trusted Artifact Signer
- Red Hat Trusted Profile Analyzer
- Red Hat build of Apache Camel - HawtIO 4
- Red Hat build of Apache Camel for Spring Boot 4
- Red Hat build of Apicurio Registry 3
- Self-service automation portal 2
- streams for Apache Kafka 2
- streams for Apache Kafka 3
Timeline
- 2026-10-02 Threatist record created from CVE-2026-59868
- 2026-10-03 Alias added: GHSA-g796-fgmg-93mv
- 2026-10-09 Affected versions changed · Red Hat
- 2026-10-21 EPSS moved to the 50th–90th percentile
- 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-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-2026-38621 js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases CVSS 3.1MEDIUM 5.3
- TI-2025-40064 js-yaml has prototype pollution in merge (<<) CVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-59868 · CVE Program
- CVE-2026-59868 · NVD
- FIRST EPSS
- GHSA-g796-fgmg-93mv · GitHub Advisory Database · CC BY 4.0
- CVE-2026-59868 · 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