Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nodeca | js-yaml | >= 5.0.0, < 5.2.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | node-js-yaml | No fix yet | — |
| Ubuntu 26.04 LTS | node-js-yaml | No fix yet | — |
| Ubuntu 25.10 | node-js-yaml | No fix yet | — |
| Ubuntu 24.04 LTS | node-js-yaml | No fix yet | — |
| Ubuntu 22.04 LTS | node-js-yaml | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | node-js-yaml | No fix yet | — |
| Ubuntu 18.04 LTS | node-js-yaml | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | dotnet8.0 +4 | 8.0.128-1.hum1 | RHSA-2026:26994 |
| Red Hat Hardened Images 1 | nodejs20 +6 | 20.20.2-1.hum1 | RHSA-2026:9455 |
| Red Hat Hardened Images 1 | nodejs20-npm | 10.8.2-1.20.20.2.1.hum1 | RHSA-2026:9455 |
| Red Hat Hardened Images 1 | nodejs22 +6 | 1:22.23.1-2.hum1 | RHSA-2026:35272 |
| Red Hat Hardened Images 1 | nodejs22-npm | 1:10.9.8-1.22.23.1.2.hum1 | RHSA-2026:35272 |
| Red Hat Hardened Images 1 | nodejs24 +6 | 1:24.18.0-0.2.hum1 | RHSA-2026:34478 |
| Red Hat Hardened Images 1 | nodejs24-npm | 1:11.16.0-1.24.18.0.0.2.hum1 | RHSA-2026:34478 |
| Red Hat Hardened Images 1 | nodejs25 +6 | 25.9.0-1.1.hum1 | RHSA-2026:7378 |
| Red Hat Hardened Images 1 | nodejs25-npm | 11.12.1-1.25.9.0.1.1.hum1 | RHSA-2026:7378 |
| Red Hat Hardened Images 1 | nodejs26 +6 | 1:26.4.0-1.3.hum1 | RHSA-2026:33866 |
| Red Hat Hardened Images 1 | nodejs26-npm | 1:11.17.0-1.26.4.0.1.3.hum1 | RHSA-2026:33866 |
| Red Hat Hardened Images 1 | rust +18 | 1.96.1-1.hum1 | RHSA-2026:34975 |
| Red Hat Hardened Images 1 | v8-13.6-devel | 3:13.6.233.17-1.24.18.0.0.2.hum1 | RHSA-2026:34478 |
| Red Hat Hardened Images 1 | v8-14.6-devel | 3:14.6.202.34-1.26.4.0.1.3.hum1 | RHSA-2026:33866 |
| Red Hat Hardened Images 1 | yarnpkg | 1.22.22-18.1.hum1 | RHSA-2026:7655 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | js-yaml | >= 5.0.0, < 5.2.0 | 5.2.0 | GHSA-g796-fgmg-93mv |
Advisories 9
- RHSA-2026:33866 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:34478 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:35272 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:7655 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:7378 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:26994 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:9455 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:34975 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- WID-SEC-2026-3221 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 13, 2026