{"id":"CVE-2026-106557","aliases":["GHSA-f7v3-xhm6-w245"],"url":"https://o3.security/vulnerability/CVE-2026-106557","summary":"Backstage: Improper input validation in TechDocs Markdown extension configuration","details":"### Impact\n\nAn authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary. Depending on deployment configuration, this may expose sensitive backend-host data or internal network resources.\n\n### Patches\n\nPatched in `@backstage/plugin-techdocs-node` version `1.15.4`.\n\nAdopters must also use `pymdown-extensions` version `10.21.3` or newer, normally through `mkdocs-techdocs-core` version `1.7.0` or newer. `@backstage/plugin-techdocs-node` does not control the Python dependencies used by the generator; with an older PyMdown release, snippets may remain vulnerable to file inclusion even after their configuration is sanitized.\n\n### Workarounds\n\n- Generate TechDocs only from trusted repositories with reviewed MkDocs configuration.\n- Use isolated build environments with restricted filesystem access and network egress.\n- Prefer externally generated TechDocs with appropriately sandboxed CI.","published":"2026-10-07T16:22:53.320Z","modified":"2026-10-21T02:54:35.519699548Z","cvss":{"score":7.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"@backstage/plugin-techdocs-node","fixedVersion":"1.15.4"}],"fix":{"url":"https://github.com/backstage/backstage/commit/017ace52d9b327ededc6704cf17799c875ae0f29","label":"backstage/backstage@017ace5"},"references":[{"type":"WEB","url":"https://github.com/backstage/backstage/releases/tag/v1.50.5"},{"type":"WEB","url":"https://github.com/backstage/backstage/releases/tag/v1.54.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/106xxx/CVE-2026-106557.json"},{"type":"ADVISORY","url":"https://github.com/backstage/backstage/security/advisories/GHSA-f7v3-xhm6-w245"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-106557"},{"type":"FIX","url":"https://github.com/backstage/backstage/commit/017ace52d9b327ededc6704cf17799c875ae0f29"},{"type":"FIX","url":"https://github.com/backstage/backstage/commit/2d9de4ca117a529de4b6ed7dfb7aa507ca7b3f91"},{"type":"PACKAGE","url":"https://github.com/backstage/backstage"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:54:35.519699548Z"}}