CVE-2026-84375Public exploitHinoki check available

Service interruption via uncounted empty merge sources

Published Sep 1, 2026 · Updated Sep 2, 2026

Denial of service in Nodeca js-yaml 3.0.0 through 3.15.1 and 4.0.0 through 4.3.1 allows remote attackers to consume CPU via crafted YAML. The loaders iterate every empty mapping in an aliased merge sequence but add no budget units to maxTotalMergeKeys, producing O(N × K) work without reaching the limit. Merge processing is enabled by default in these release lines, but exposure requires a consuming application to parse attacker-controlled YAML.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Nodeca js-yaml 3.0.0 through 3.15.1 and 4.0.0 through 4.3.1 allows remote attackers to consume CPU via crafted YAML. The loaders iterate every empty mapping in an aliased merge sequence but add no budget units to maxTotalMergeKeys, producing O(N × K) work without reaching the limit. Merge processing is enabled by default in these release lines, but exposure requires a consuming application to parse attacker-controlled YAML.

The record

CVE
CVE-2026-84375
Published
Sep 1, 2026
Updated
Sep 2, 2026
Vendor
Nodeca
Product
js-yaml
Classifications
CWE-400, CWE-407, T1499.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.0.0, < 3.15.2
  2. Affected versionversion=>= 4.0.0, < 4.3.2

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Nodeca · js-yamlversion=>= 3.0.0, < 3.15.2; version=>= 4.0.0, < 4.3.2

Published CVSS scores

7.5GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo