CVE-2026-84375High· 7.5▾ Twilightjs-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, maxTotalMergeKeys in lib/js-yaml/loader.js and lib/loader.js does not count empty mapping sources while processing the merge key <<. An attacker c…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.4%
Last analysed / modified upstream
0.4% → 0.5%
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 until 3.15.2, 4.3.2, and 5.4.1, 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. In v3 & v4, merge is enabled by default so the severity score is higher. This issue is fixed in versions 3.15.2, 4.3.2, and 5.4.1.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
js-yaml >= 4.0.0, < 4.3.2js-yaml >= 3.0.0, < 3.15.2Patched in:
js-yaml 4.3.2js-yaml 3.15.2Source: https://github.com/advisories/GHSA-2883-xcg3-v3hh
Connected by shared product, vendor, weakness, or advisory.
GHSA-r3ph-w7gj-g6xmMedium· 5.3js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources
CVE-2026-59870High· 7.5js-yaml is a JavaScript YAML parser and dumper
CVE-2026-104861High· 7.5probe-image-size gets image dimensions without downloading the entire file
CVE-2026-59868Medium· 5.3js-yaml is a JavaScript YAML parser and dumper
CVE-2018-14567Medium· 6.5libxml2 2.9.8, if --with-lzma is used, allows remote attackers to cause a denial of service (infinite loop) via a crafted XML file that triggers LZMA_MEMLIMIT_ERROR, as demonstrated by xmllint, a different vulnerability than CVE-2015-803…
GHSA-5p4m-2wfm-xmqjHigh· 7.5JS-YAML: Quadratic CPU consumption in !!omap resolution (3.x and 4.x) — CVE-2026-59870 fix not backported