{"id":"CVE-2026-84375","title":"js-yaml is a JavaScript YAML parser and dumper","summary":"js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400","CWE-407","CWE-835"],"vendor":"js-yaml","product":"js-yaml","affected":["js-yaml >= 4.0.0, < 4.3.2","js-yaml >= 3.0.0, < 3.15.2"],"patched":["js-yaml 4.3.2","js-yaml 3.15.2"],"published":"2026-09-01","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:09:13.080","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-84375","references":[{"url":"https://github.com/nodeca/js-yaml/commit/3485bc06ff8a0251505f44a00414d90df2466639","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/commit/6a8e05f9a485188ed730ac81e81ae221352ef480","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/commit/d90b6612a5a84385bdcb556c44578eac76dc0f6b","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/pull/797","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/releases/tag/3.15.2","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/releases/tag/4.3.2","label":"security-advisories@github.com"},{"url":"https://github.com/nodeca/js-yaml/security/advisories/GHSA-2883-xcg3-v3hh","label":"security-advisories@github.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84375"},{"url":"https://github.com/advisories/GHSA-2883-xcg3-v3hh"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84375.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-84375"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2527118"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-84375"},{"url":"https://access.redhat.com/errata/RHSA-2026:62810"},{"url":"https://access.redhat.com/errata/RHSA-2026:63165"},{"url":"https://access.redhat.com/errata/RHSA-2026:62813"},{"url":"https://access.redhat.com/errata/RHSA-2026:66084"},{"url":"https://access.redhat.com/errata/RHSA-2026:67711"},{"url":"https://access.redhat.com/errata/RHSA-2026:67714"},{"url":"https://access.redhat.com/errata/RHSA-2026:67279"},{"url":"https://access.redhat.com/errata/RHSA-2026:68044"},{"url":"https://access.redhat.com/errata/RHSA-2026:68253"},{"url":"https://access.redhat.com/errata/RHSA-2026:68006"},{"url":"https://access.redhat.com/errata/RHSA-2026:68254"},{"url":"https://access.redhat.com/errata/RHSA-2026:63164"},{"url":"https://access.redhat.com/errata/RHSA-2026:68681"},{"url":"https://access.redhat.com/errata/RHSA-2026:67724"},{"url":"https://access.redhat.com/errata/RHSA-2026:68754"},{"url":"https://access.redhat.com/errata/RHSA-2026:68687"},{"url":"https://access.redhat.com/errata/RHSA-2026:68689"},{"url":"https://access.redhat.com/errata/RHSA-2026:68691"},{"url":"https://access.redhat.com/errata/RHSA-2026:68690"},{"url":"https://access.redhat.com/errata/RHSA-2026:69289"}],"tags":["nvd","ghsa","npm","csaf","vex","red-hat"],"epss":0.00385,"epssPercentile":0.32401,"aliases":["GHSA-2883-xcg3-v3hh"],"ecosystem":"npm","ingestedAt":"2026-09-08T22:12:30.968Z","slug":"CVE-2026-84375","body":"## Overview\n\njs-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2 and 4.3.2, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker can alias a large sequence of empty mappings into many merge targets, causing O(N * K) processing while totalMergeKeys remains unchanged and the configured resource limit is never reached. A relatively small YAML document can therefore cause prolonged CPU consumption in applications that parse untrusted YAML, and merge processing is enabled by default on these release lines. This issue is fixed in versions 3.15.2 and 4.3.2.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-84375)\n\nAffected packages:\n\n- `js-yaml >= 4.0.0, < 4.3.2`\n- `js-yaml >= 3.0.0, < 3.15.2`\n\nPatched in:\n\n- `js-yaml 4.3.2`\n- `js-yaml 3.15.2`\n\nSource: https://github.com/advisories/GHSA-2883-xcg3-v3hh\n\n## Vendor advisories\n\n- **RHSA-2026:62810** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62810)\n- **RHSA-2026:63165** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63165)\n- **RHSA-2026:62813** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62813)\n- **RHSA-2026:66084** · Red Hat · fixed in: Red Hat Quay 3.10 · released 2026-09-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:66084)\n- **Red Hat VEX** · Moderate · affected: Multicluster Engine for Kubernetes, Network Observability Operator, Node HealthCheck Operator, OpenShift Lightspeed, OpenShift Pipelines, Red Hat Advanced Cluster Management for Kubernetes 2, … · no fix planned: Red Hat Ansible Automation Platform 2, Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Directory Server 13, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-84375.json)\n- **RHSA-2026:67711** · Red Hat · fixed in: Red Hat Advanced Cluster Security for Kubernetes 4.10 · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67711)\n- **RHSA-2026:67714** · Red Hat · fixed in: Red Hat Advanced Cluster Security for Kubernetes 4.11 · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67714)\n- **RHSA-2026:67279** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.7 · released 2026-09-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:67279)\n- **RHSA-2026:68044** · Red Hat · fixed in: Red Hat Edge Manager 1.1 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68044)\n- **RHSA-2026:68253** · Red Hat · fixed in: Red Hat Edge Manager 1.1 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68253)\n- **RHSA-2026:68006** · Red Hat · fixed in: Red Hat Edge Manager 1.2 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68006)\n- **RHSA-2026:68254** · Red Hat · fixed in: Red Hat Edge Manager 1.2 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68254)\n- **RHSA-2026:63164** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63164)\n- **RHSA-2026:69289** · Red Hat · fixed in: Red Hat Discovery 2 · released 2026-09-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:69289)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}