CVE-2026-106557

Backstage: Improper input validation in TechDocs Markdown extension configuration

Published Oct 7, 2026 CVSS 3.1 · 7.7 High EPSS < 1% KEV · Not listed
Description
Backstage is an open framework for building developer portals. Prior to 1.14.6 and 1.15.4, the @backstage/plugin-techdocs-node package did not sufficiently validate TechDocs Markdown extension configuration. An authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary, potentially exposing backend-host data or internal network resources. This issue is fixed in versions 1.14.6 and 1.15.4 when pymdown-extensions 10.21.3 or later is also used, normally through mkdocs-techdocs-core 1.7.0 or later.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-f7v3-xhm6-w245 Backstage has improper input validation in TechDocs Markdown extension configuration
History
Type Values Removed Values Added
First Time appeared Backstage
Backstage backstage
Backstage plugin-techdocs-node
Vendors & Products Backstage
Backstage backstage
Backstage plugin-techdocs-node
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Backstage is an open framework for building developer portals. Prior to 1.14.6 and 1.15.4, the @backstage/plugin-techdocs-node package did not sufficiently validate TechDocs Markdown extension configuration. An authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary, potentially exposing backend-host data or internal network resources. This issue is fixed in versions 1.14.6 and 1.15.4 when pymdown-extensions 10.21.3 or later is also used, normally through mkdocs-techdocs-core 1.7.0 or later.
Title Backstage: Improper input validation in TechDocs Markdown extension configuration
Weaknesses CWE-22
CWE-918
References
Metrics cvssV3_1

{'score': 7.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 7, 2026, 5:47 PM
Reserved
Oct 6, 2026, 8:31 PM
Status
Awaiting Analysis
Published
Oct 7, 2026, 5:16 PM
Modified
Oct 8, 2026, 9:33 PM