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Fencer Vulns
medium 4.3

CVE-2026-33532 json

yaml is vulnerable to Stack Overflow via deeply nested YAML collections

published 2026-03-25 7 mo ago modified 2026-09-10 1 mo ago also GHSA-48c2-rrv3-qjmp , EUVD-2026-16363

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

`yaml` is a YAML parser and serialiser for JavaScript. Parsing a YAML document with a version of `yaml` on the 1.x branch prior to 1.10.3 or on the 2.x branch prior to 2.8.3 may throw a RangeError due to a stack overflow. The node resolution/composition phase uses recursive function calls without a depth bound. An attacker who can supply YAML for parsing can trigger a `RangeError: Maximum call stack size exceeded` with a small payload (~2–10 KB). The `RangeError` is not a `YAMLParseError`, so applications that only catch YAML-specific errors will encounter an unexpected exception type. Depending on the host application's exception handling, this can fail requests or terminate the Node.js process. Flow sequences allow deep nesting with minimal bytes (2 bytes per level: one `[` and one `]`). On the default Node.js stack, approximately 1,000–5,000 levels of nesting (2–10 KB input) exhaust the call stack. The exact threshold is environment-dependent (Node.js version, stack size, call stack depth at invocation). Note: the library's `Parser` (CST phase) uses a stack-based iterative approach and is not affected. Only the compose/resolve phase uses actual call-stack recursion. All three public parsing APIs are affected: `YAML.parse()`, `YAML.parseDocument()`, and `YAML.parseAllDocuments()`. Versions 1.10.3 and 2.8.3 contain a patch.

Patch / fix

  • npm yaml 1.10.3, 2.8.3
  • eemeli yaml 1.10.3, 2.8.3
  • node-yaml Debian 14 2.8.3+~cs0.4.0-1

debian advisories DEBIAN-CVE-2026-33532

  • alloy SLE Module for Basesystem 15 SP7 1.17.1-150700.15.23.1
  • alloy SLES for SAP applications 16.0, SLES 16.0 1.17.0-160000.1.1

suse advisories SUSE-SU-2026:2824-1SUSE-SU-2026:22575-1

  • alloy openSUSE Leap 16.0 1.17.0-160000.1.1
  • alloy openSUSE Tumbleweed 1.17.0-1.1

opensuse advisories openSUSE-SU-2026:21251-1openSUSE-SU-2026:11053-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33532 updated cvss 6.5

yaml: yaml: Denial of Service via deeply nested YAML document parsing

  • Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-hub-ui-rhel8, openshift-pipelines/pipelines-hub-ui-rhel9, openshift-pipelines/pipelines-console-plugin-rhel9 Red Hat 3scale API Management Platform 2 3scale-amp20/system, 3scale-amp21/system, 3scale-amp22/system, 3scale-amp24/system, 3scale-amp25/system, 3scale-amp26/system, +3 more Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat AMQ Broker 7 yaml, amq7-tech-preview/amq-broker-jolokia-api-server-rhel9
    +26 more products
    Red Hat Ansible Automation Platform 2 automation-gateway, automation-controller, automation-platform-ui, automation-eda-controller, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, +1 more Red Hat build of Apicurio Registry 2 yaml Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Build of Keycloak yaml Red Hat build of OptaPlanner 8 yaml Red Hat Build of Podman Desktop podman-desktop-macos-1-0, podman-desktop-windows-1-0 Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9, rhdh/backstage-community-plugin-catalog-backend-module-scaffolder-relation-processor Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Enterprise Linux 8 pcs, grafana, mozjs60, pcs-snmp, grafana-pcp, grafana-loki, +16 more Red Hat Enterprise Linux 9 gjs, pcs, grafana, pcs-snmp, grafana-pcp, grafana-selinux Red Hat Enterprise Linux 10 grafana, ruby4.0, grafana-pcp Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/disk-image-cuda-rhel9 Red Hat Fuse 7 yaml Red Hat JBoss Enterprise Application Platform 8 yaml Red Hat JBoss Enterprise Application Platform Expansion Pack yaml Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel8, rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9, rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9, +13 more Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat Openshift Data Foundation 4 odf4/mcg-core-rhel9, odf4/odf-console-rhel9, odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/dashboard-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin-rhel9 Red Hat Quay 3 quay/quay-rhel8 Red Hat Satellite 6 nodejs-emotion, satellite/iop-vulnerability-frontend-rhel9 Red Hat Single Sign-On 7 yaml Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal Red Hat streams for Apache Kafka 2 yaml Red Hat streams for Apache Kafka 3 yaml
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/eemeli/yaml/security/advisories/GHSA-48c2-rrv3-qjmp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm yaml
>=2.0.0, <2.8.3
>=1.0.0, <1.10.3
2.8.3
1.10.3

Affected products

  • eemeli yaml

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.