UBUNTU-CVE-2026-59870
A vulnerability in js-yaml versions from 5.0.0 before 5.2.1 causes excessive CPU consumption due to a quadratic time complexity in processing the !!omap tag. This occurs because the YAML11_SCHEMA support uses a linear duplicate-key scan on every insertion, leading to O(n^2) CPU usage when parsing crafted ordered-map documents. The issue is fixed in version 5.2.1. The affected Ubuntu package versions include 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2.
AI Analysis
Technical Summary
The js-yaml JavaScript library versions from 5.0.0 up to but not including 5.2.1 contain a performance vulnerability in the YAML11_SCHEMA implementation for the !!omap tag. Specifically, the omapTag.addItem() function performs a linear duplicate-key scan on every insertion, resulting in O(n^2) CPU consumption when yaml.load() parses a specially crafted ordered-map document. This can lead to denial of service via resource exhaustion. The vulnerability is resolved in version 5.2.1. The Ubuntu packages affected are 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2.
Potential Impact
This vulnerability causes high CPU usage (denial of service) when parsing maliciously crafted YAML documents containing ordered maps. There is no impact on confidentiality or integrity. The vulnerability can be exploited remotely without authentication and requires no user interaction.
Mitigation Recommendations
Upgrade js-yaml to version 5.2.1 or later where this issue is fixed. The affected Ubuntu package versions 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2 should be updated to versions that include the fix. Patch status is confirmed fixed in 5.2.1 upstream; check Ubuntu vendor advisories for updated package versions.
UBUNTU-CVE-2026-59870
Description
A vulnerability in js-yaml versions from 5.0.0 before 5.2.1 causes excessive CPU consumption due to a quadratic time complexity in processing the !!omap tag. This occurs because the YAML11_SCHEMA support uses a linear duplicate-key scan on every insertion, leading to O(n^2) CPU usage when parsing crafted ordered-map documents. The issue is fixed in version 5.2.1. The affected Ubuntu package versions include 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2.
CVSS v3.1
Score 5.3medium
Affected software
pkg:deb/ubuntu/[email protected]+dfsg-1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]+dfsg-2?arch=source&distro=focalpkg:deb/ubuntu/[email protected]+dfsg+~4.0.5-6?arch=source&distro=jammypkg:deb/ubuntu/[email protected]+dfsg+~4.0.5-7?arch=source&distro=noblepkg:deb/ubuntu/[email protected]+dfsg+~4.0.5-7?arch=source&distro=questingpkg:deb/ubuntu/[email protected]+dfsg+~4.0.9-1?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The js-yaml JavaScript library versions from 5.0.0 up to but not including 5.2.1 contain a performance vulnerability in the YAML11_SCHEMA implementation for the !!omap tag. Specifically, the omapTag.addItem() function performs a linear duplicate-key scan on every insertion, resulting in O(n^2) CPU consumption when yaml.load() parses a specially crafted ordered-map document. This can lead to denial of service via resource exhaustion. The vulnerability is resolved in version 5.2.1. The Ubuntu packages affected are 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2.
Potential Impact
This vulnerability causes high CPU usage (denial of service) when parsing maliciously crafted YAML documents containing ordered maps. There is no impact on confidentiality or integrity. The vulnerability can be exploited remotely without authentication and requires no user interaction.
Mitigation Recommendations
Upgrade js-yaml to version 5.2.1 or later where this issue is fixed. The affected Ubuntu package versions 3.9.1+dfsg-1, 3.10.0+dfsg-1, and 3.13.1+dfsg-2 should be updated to versions that include the fix. Patch status is confirmed fixed in 5.2.1 upstream; check Ubuntu vendor advisories for updated package versions.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-59870
- Osv Schema Version
- 1.7.0
- Aliases
- []
- Ecosystems
- ["Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Database Specific Severity
- null
- Cvss Version
- 3.1
Threat ID: 6a58b45968715ace43d6bbc4
Added to database: 07/16/2026, 10:37:13 UTC
Last enriched: 07/16/2026, 11:32:42 UTC
Last updated: 07/31/2026, 19:24:49 UTC
Views: 5
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