CVE-2026-106558 · GHSA-qmw3-745m-w99g
Backstage: Improper validation of TechDocs MkDocs configuration
- Risk score
- 66/100
- CVSS
- 8.8 v3.1
- Exploit chance (30 days)
- 0.5%
- Published
- 7 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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 Tech…
- Affected
- @backstage/plugin-techdocs-node (npm) < 1.15.4
- Fix
- Upgrade @backstage/plugin-techdocs-node to 1.15.4 or later.
- Exploitation
- No known exploitation
Story map
At a glance
@backstage/plugin-techdocs-node: Amber, patch this week. Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When TechDocs is configured to build documentation locally or in a container, a user with write access to a registere…
The flaws
- CVE-2026-106558: Backstage: Improper validation of TechDocs MkDocs configuration (CVSS 8.8 · EPSS 0%)
- CVE-2026-106509: Backstage: Improper validation of MkDocs theme configuration in TechDocs (CVSS 8.8 · EPSS 0%)
- CVE-2026-106505: Backstage: Bypass of MkDocs configuration sanitizer in TechDocs backend (CVSS 8.5 · EPSS 0%)
- CVE-2026-106510: Backstage: Remote code execution via crafted markdown_extensions in TechDocs mkdocs.yml (CVSS 7.7 · EPSS 0%)
The fix
Upgrade @backstage/plugin-techdocs-node: 1.14.8 · 1.15.6 · 2.0.1 · 1.14.6 · 1.15.4 or later on your release line
Who is exposed: @backstage/plugin-techdocs-node (npm) < 1.15.4
Where it stands
- Public proof of concept
Connects to
- Same weakness: Unsafe deserialisation (CWE-502). 250 other warnings in 30 days
- Same product: Earlier @backstage/plugin-techdocs-node warnings. 3 in the last 90 days
Why it is Amber
- CVSS 8.8 high
- On your watchlist: npm
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| @backstage/plugin-techdocs-node | npm | < 1.15.4 | 1.15.4 |
References
- https://github.com/advisories/GHSA-qmw3-745m-w99g
- https://github.com/backstage/backstage/security/advisories/GHSA-qmw3-745m-w99g
- https://nvd.nist.gov/vuln/detail/CVE-2026-106558
- 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
- https://github.com/backstage/backstage/releases/tag/v1.55.2
- https://github.com/advisories/GHSA-qmw3-745m-w99g
Original 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.
Last activity 7 Oct 2026. Patch Forecast updates every hour.