High [CVE-2026-59868] Denial of Service via quadratic CPU time parsing with merge keys
This high-severity Red Hat Linux advisory covers CVE-2026-59868 affecting Red Hat Discovery 2, Red Hat Hardened Images.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one.
This issue is fixed in version 5.2.0. This can lead to a significant increase in CPU time required to parse the document, resulting in a Denial of Service (DoS) for the affected system. js-yaml versions 5.0.0 through 5.1.x are vulnerable to a denial of service.
This can be triggered via yaml.load() on untrusted YAML input that uses merge keys. Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-1333. Affected Red Hat products: Red Hat Discovery 2; Red Hat Hardened Images.
Is CVE-2026-59868 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-59868 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-59868?
Upgrade to a fixed release named by Red Hat:
- 5.2.0
- discovery/discovery-ui-rhel9:1788206196
- dotnet8-0-main-8.0.128-1.hum1
- nodejs26-main-11.17.0-1.26.4.0.1.3.hum1
- nodejs26-main-26.4.0-1.3.hum1
- nodejs24-main-11.16.0-1.24.18.0.0.2.hum1
- nodejs24-main-24.18.0-0.2.hum1
- rust-main-1.96.1-1.hum1
- nodejs22-main-10.9.8-1.22.23.1.2.hum1
- nodejs22-main-22.23.1-2.hum1
- nodejs25-main-11.12.1-1.25.9.0.1.1.hum1
- nodejs25-main-25.9.0-1.1.hum1
12 more fixed releases are listed below.
Confirm against the vendor advisory before you patch.
- < 5.0.0
- < 5.2.0
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
- 5.2.0
- discovery/discovery-ui-rhel9:1788206196
- dotnet8-0-main-8.0.128-1.hum1
- nodejs26-main-11.17.0-1.26.4.0.1.3.hum1
- nodejs26-main-26.4.0-1.3.hum1
- nodejs24-main-11.16.0-1.24.18.0.0.2.hum1
- nodejs24-main-24.18.0-0.2.hum1
- rust-main-1.96.1-1.hum1
- nodejs22-main-10.9.8-1.22.23.1.2.hum1
- nodejs22-main-22.23.1-2.hum1
- nodejs25-main-11.12.1-1.25.9.0.1.1.hum1
- nodejs25-main-25.9.0-1.1.hum1
- yarnpkg-main-1.22.22-18.1.hum1
- nodejs20-main-10.8.2-1.20.20.2.1.hum1
- nodejs20-main-20.20.2-1.hum1
- RHSA-2026:61783
- RHSA-2026:26994
- RHSA-2026:33866
- RHSA-2026:34478
- RHSA-2026:34975
- RHSA-2026:35272
- RHSA-2026:7378
- RHSA-2026:7655
- RHSA-2026:9455
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Mitigation checklist
- Upgrade to js-yaml 5.2.0 or later. Where an immediate upgrade is not possible, avoid parsing untrusted YAML documents that use merge keys ('<<'), or apply size and time limits when parsing untrusted YAML input.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
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