{"cve":"CVE-2026-106558","nvd":{"published":"2026-10-07T15:17:15.713","modified":"2026-10-13T14:25:12.163","status":"Analyzed","description":"Backstage is an open framework for building developer portals. Prior to 1.14.8, 1.15.6, and 2.0.1, the @backstage/plugin-techdocs-node package improperly validated mapping-style markdown_extensions configuration. An authenticated attacker who can register or influence an SCM-backed documentation source may bypass TechDocs sanitization and cause Python objects to be imported and instantiated in the generator runtime, leading to arbitrary code execution. Earlier fixes in versions 1.14.6 and 1.15.4 did not fully address the supported mapping representation of markdown_extensions. Impact is greatest when documentation generation runs with backend credentials, filesystem access, or internal network access. This issue is fixed in versions 1.14.8, 1.15.6, and 2.0.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-502"],"references":["https://github.com/backstage/backstage/commit/32723a0fe4e12ed80535fc65d5331765c55aa91b","https://github.com/backstage/backstage/commit/944edb51c8524d3664b18f2d57ba101b1c93b709","https://github.com/backstage/backstage/commit/f18e9abcc6051491862b15e4fc60e69f8d52310c","https://github.com/backstage/backstage/releases/tag/v1.50.7","https://github.com/backstage/backstage/releases/tag/v1.54.9"],"products":["linuxfoundation:backstage","linuxfoundation:backstage_plugin-techdocs-node"],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-106558","score":0.00469,"percentile":0.40331,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-qmw3-745m-w99g","url":"https://osv.dev/vulnerability/GHSA-qmw3-745m-w99g","summary":"Backstage: Improper validation of TechDocs MkDocs configuration","modified":"2026-10-07T18:15:12.165363848Z","packages":[{"ecosystem":"npm","name":"@backstage/plugin-techdocs-node","purl":"pkg:npm/%40backstage/plugin-techdocs-node","ranges":["<1.15.4"],"fixed":["1.15.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}