js-yaml has prototype pollution in merge (<<)
Priority LOW 30CWE-1321Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Partial Red Hat: 4 fixed, 61 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
js-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (`__proto__`). All users who parse untrusted yaml documents may be impacted. The problem is patched in js-yaml 4.1.1 and 3.14.2. Users can protect against this kind of attack on the server by using `node --disable-proto=delete` or `deno` (in Deno, pollution protection is on by default).
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00423 36th percentileScored 2026-11-07
Fix Partial js-yaml (nodeca): 4.1.1, 3.14.2js-yaml (npm): 4.1.1, 3.14.2Red Hat: 4 advisoriesRed Hat: 4 fixed, 61 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 4.1.1; before 3.14.2 | 4.1.1, 3.14.2 | Patch available | CNA |
| — | js-yaml (npm) | 4.0.0 to before 4.1.1 | 4.1.1 | Patch available | GHSA-mh29-5h37-fv8m |
| — | js-yaml (npm) | before 3.14.2 | 3.14.2 | Patch available | GHSA-mh29-5h37-fv8m |
- js-yaml Vendornodeca Affected 4.0.0 to before 4.1.1; before 3.14.2 Fixed in 4.1.1, 3.14.2 Patch available CNA
- js-yaml (npm) Vendor— Affected 4.0.0 to before 4.1.1 Fixed in 4.1.1 Patch available GHSA-mh29-5h37-fv8m
- js-yaml (npm) Vendor— Affected before 3.14.2 Fixed in 3.14.2 Patch available GHSA-mh29-5h37-fv8m
Remediation
- Fix · CNA js-yaml (nodeca) Fixed in 4.1.1, 3.14.2
- Fix · GHSA-mh29-5h37-fv8m js-yaml (npm) Fixed in 4.1.1 Advisory →
- Fix · GHSA-mh29-5h37-fv8m js-yaml (npm) Fixed in 3.14.2 Advisory →
Red Hat 4 advisories
- RHSA-2026:83548 Released 2026-10-15 · Red Hat rating ImportantRed Hat Ceph Storage
- Red Hat Ceph Storage 7.1 registry.redhat.io/rhceph/grafana-rhel9, registry.redhat.io/rhceph/rhceph-7-rhel9
- 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-2026:26411 Released 2026-06-16 · Red Hat rating ImportantNew container image: rhceph-9.0
- Red Hat Ceph Storage 9.0 registry.redhat.io/rhceph/grafana-rhel10, registry.redhat.io/rhceph/rhceph-9-rhel9
Show 1 more Red Hat advisories
- RHSA-2026:15979 Released 2026-05-11 · Red Hat rating ImportantRed Hat Ceph Storage
- Red Hat Ceph Storage 8.1 registry.redhat.io/rhceph/grafana-rhel9
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 |
| Gatekeeper 3 | Affected | No fix yet: Fix deferred |
| Logging Subsystem for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 7 | 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 |
| Migration Toolkit for Virtualization | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Multicluster Global Hub | 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 API for Data Protection | 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 Ceph Storage 6 | Affected | No fix yet |
| Red Hat Ceph Storage 7 | Affected | No fix yet |
| Red Hat Ceph Storage 8 | Affected | No fix yet |
| Red Hat Ceph Storage 9 | Affected | No fix yet |
| 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 Directory Server 13 | Affected | No fix yet: Fix deferred |
| Red Hat Discovery 2 | Affected | No fix yet: Fix deferred |
| Red Hat Edge Manager preview | 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 yet: Fix deferred |
| Red Hat Fuse 7 | Affected | No fix yet: Fix deferred |
| 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 AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | 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 OpenShift distributed tracing 3 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 16.2 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 17.1 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Process Automation 7 | 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 Apicurio Registry 2 | Affected | No fix yet: Fix deferred |
| Red Hat build of OptaPlanner 8 | 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 Ceph Storage 7.1 | Fixed | RHSA-2026:83548 |
| Red Hat Ceph Storage 8.1 | Fixed | RHSA-2026:15979 |
| Red Hat Ceph Storage 9.0 | Fixed | RHSA-2026:26411 |
| Red Hat Openshift Data Foundation 4.18 | Fixed | RHSA-2026:56431 |
Not affected: 4 products
- Red Hat Ceph Storage 7.1
- Red Hat Ceph Storage 8.1
- Red Hat Ceph Storage 9.0
- Red Hat Openshift Data Foundation 4.18
Timeline
- 2026-10-02 Threatist record created from CVE-2025-64718
- 2026-10-03 Alias added: GHSA-mh29-5h37-fv8m
- 2026-10-09 Affected versions changed · Red Hat
- 2026-10-16 Fix available: RHSA-2026:83548 · Red Hat
- 2026-10-16 Fix available: Red Hat Ceph Storage 7.1 · Red Hat
- 2026-10-27 Affected versions changed · Red Hat
References
Patch 2
Advisory 3
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-2026-38621 js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases CVSS 3.1MEDIUM 5.3
Sources
- CVE-2025-64718 · CVE Program
- CVE-2025-64718 · NVD
- FIRST EPSS
- GHSA-mh29-5h37-fv8m · GitHub Advisory Database · CC BY 4.0
- CVE-2025-64718 · 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