CVE-2026-106509
Backstage: Improper validation of MkDocs theme configuration in TechDocs
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 registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
7.7
Backstage: Improper validation of MkDocs theme configuration in TechDocs
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 registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
- Record
CVE-2026-106509- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - Weakness
- CWE-94, CWE-1336
- Updated
- 2026-11-02
EUVDEUVD-2026-94074
7.7
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 registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
- Record
EUVD-2026-94074- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8w7q-29mw-gf5c
7.7
Backstage: Improper validation of MkDocs theme configuration in TechDocs
Impact
When TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process.
Patches
Patched in @backstage/plugin-techdocs-node version 1.15.4
Workarounds
- Configure TechDocs with
techdocs.generator.runIn: 'docker'instead of'local'to provide container isolation, though this does not fully mitigate the risk. - Restrict write access to repositories registered in the Backstage catalog to trusted users.
- Record
GHSA-8w7q-29mw-gf5c- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - Weakness
- CWE-94, CWE-1336
- Updated
- 2026-11-02
NVD
7.7
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 registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
- Record
CVE-2026-106509- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94, CWE-1336
- Updated
- 2026-11-02
OSV
7.7
Backstage: Improper validation of MkDocs theme configuration in TechDocs
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 registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.
- Record
CVE-2026-106509- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - Weakness
- CWE-1336, CWE-94
- Updated
- 2026-11-02
OSVGHSA-8w7q-29mw-gf5c
7.7
Backstage: Improper validation of MkDocs theme configuration in TechDocs
Impact
When TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process.
Patches
Patched in @backstage/plugin-techdocs-node version 1.15.4
Workarounds
- Configure TechDocs with
techdocs.generator.runIn: 'docker'instead of'local'to provide container isolation, though this does not fully mitigate the risk. - Restrict write access to repositories registered in the Backstage catalog to trusted users.
- Record
GHSA-8w7q-29mw-gf5c- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L - Weakness
- CWE-1336, CWE-94
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
@backstage/plugin-techdocs-nodenpm |
before 1.15.4 | 1.15.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-106509 is a high vulnerability (CVSS 7.7) in @backstage Plugin-techdocs-node, published October 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in @backstage/plugin-techdocs-node 1.15.4.
References
github.com/backstage/backstage/security/advisories/GHSA-8w7q-29mw-gf5c
github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbb
github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a9996cc9d
github.com/backstage/backstage/releases/tag/v1.50.5
github.com/backstage/backstage/releases/tag/v1.54.6
nvd.nist.gov/vuln/detail/CVE-2026-106509
github.com/advisories/GHSA-8w7q-29mw-gf5c
github.com/CVEProject/cvelistV5/tree/main/cves/2026/106xxx/CVE-2026-106509.json
github.com/backstage/backstage