js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources

Summary maxTotalMergeKeys does not count empty mappings. An attacker can repeatedly merge a large sequence of them and consume significant CPU without reaching the configured limit. Example yaml arr: &arr , , , ... N empty mappings targets: - : arr repeated K times For every target, the loader...

CVE-2026-84375

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 a large sequence of empty mappings into many merge targets,...

CVE-2026-84375 js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources

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 a large sequence of empty mappings into many merge targets,...

CVE-2026-84375 js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources

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 a large sequence of empty mappings into many merge targets,...

CVE-2026-84375

js-yaml , a widely used JavaScript YAML parser, is vulnerable to a CPU exhaustion issue in its merge-key (<