CVE catalog
CVE-2026-53550
js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same ali
- Severity
- Medium · CVSS 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.41% · Oct 25, 2026
js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | node-js-yaml | sid | 4.3.2+~4.0.9-1 | fixed |
| Debian | node-js-yaml | forky | 4.3.2+~4.0.9-1 | fixed |
| Debian | node-js-yaml | trixie | 4.1.0+dfsg+~4.0.5-7 | vulnerable |
| Debian | node-js-yaml | bookworm | 4.1.0+dfsg+~4.0.5-7 | vulnerable |
| Cpe | node-js-yaml | Not reported | Not reported | vulnerable |
| Cpe | js-yaml | Not reported | 3.15.0 | fixed |
| Cpe | js-yaml | Not reported | 4.2.0 | fixed |
| Npm | js-yaml | Not reported | 3.15.0 | fixed |
| Npm | js-yaml | Not reported | 3.15.0 | fixed |
| Opensuse | python-pydata-sphinx-theme | tumbleweed | 0.19.0-1.1 | fixed |
| Cpe | js-yaml | Not reported | 4.2.0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | node-js-yaml | source | sid | 4.2.0+~4.0.9-1 | not yet assigned | Not reported | Not reported |
| Debian | node-js-yaml | source | forky | 4.2.0+~4.0.9-1 | not yet assigned | Not reported | Not reported |
| Debian | node-js-yaml | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | node-js-yaml | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | js-yaml | cpe | Not reported | 3.15.0 | Not reported | Not reported | Not reported |
| Cpe | js-yaml | cpe | Not reported | 4.2.0 | Not reported | Not reported | Not reported |
| Npm | js-yaml | npm | Not reported | 3.15.0 | Not reported | GHSA-H67P-54HQ-RP68 | Not reported |
| Npm | js-yaml | npm | Not reported | 3.15.0 | Not reported | Not reported | Not reported |
| Opensuse | python-pydata-sphinx-theme | rpm | tumbleweed | 0.19.0-1.1 | Not reported | OPENSUSE-SU-2026:11148-1 | Not reported |
| Cpe | js-yaml | cpe | Not reported | 4.2.0 | Not reported | NVD-CVE-2026-53550 | Not reported |
Notes
[trixie] node-js-yaml: Minor issue [bookworm] node-js-yaml: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [node-js-yaml]Affected
Details (2)
4.1.0+dfsg+~4.0.5-7· all · bookwormAffected
nvd · node-js-yaml · debian · bookworm; nvd · node-js-yaml · debian · 12
4.1.0+dfsg+~4.0.5-7· all · bookwormAffected
nvd · node-js-yaml · debian · bookworm; nvd · node-js-yaml · debian · 12
[Debian 13 (Trixie)]
- [node-js-yaml]Affected
Details (2)
4.1.0+dfsg+~4.0.5-7· all · trixieAffected
nvd · node-js-yaml · debian · 13
4.1.0+dfsg+~4.0.5-7· all · trixieAffected
nvd · node-js-yaml · debian · 13
[openSUSE Tumbleweed]
- [python313-pydata-sphinx-theme]Unknown
Source package: [python-pydata-sphinx-theme]
Details (1)
0.19.0-2.2· noarch · tumbleweedUnknown · Fixed:
0.19.0-1.1Version impact unknown
nvd · python-pydata-sphinx-theme · opensuse · tumbleweed
- [python314-pydata-sphinx-theme]Unknown
Source package: [python-pydata-sphinx-theme]
Details (1)
0.19.0-2.2· noarch · tumbleweedUnknown · Fixed:
0.19.0-1.1Version impact unknown
nvd · python-pydata-sphinx-theme · opensuse · tumbleweed
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11452-1.json]
- [https://github.com/nodeca/js-yaml/security/advisories/GHSA-h67p-54hq-rp68]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-53550]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-53550]
- [https://osv.dev/vulnerability/GHSA-h67p-54hq-rp68]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:11148-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-53550]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53550.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2618.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]