Is CVE-2026-59870 in the CISA KEV catalog?

No. CVE-2026-59870 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-59870?

CVE-2026-59870 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-59870?

CVE-2026-59870 has an EPSS score of 0.36% (28th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-59870?

Upgrade js-yaml to 5.2.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-59870

MEDIUM

5.3

CVSS v3

NVD

Description

js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. This issue is fixed in version 5.2.1.

CWE-407 CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

js-yamlNVD

Affected:>= 5.0.0, < 5.2.1Fixed in:5.2.1CVE-2026-59870derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.36%probability of exploitation in 30 days

28thpercentile

Low risk: more likely to be exploited than 28% of all known CVEs.

References

Patch1

github.com

Exploit1

github.com

Release Notes1

github.com

Related Vulnerabilities

Other CWE-407 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-27223	Medium	5.2	78%	-	Fix
CVE-2022-36021	Medium	5.5	60%	-	Fix
CVE-2021-33582	High	7.5	3.1%	-	Fix
CVE-2024-43485	High	7.5	3.1%	-	Fix
CVE-2024-43484	High	7.5	2.9%	-	Fix
CVE-2016-10396	High	7.5	2.9%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-10.