Backstage: Bypass of MkDocs configuration sanitizer in TechDocs backend

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.7 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L

EPSS

• CVE-2026-106505: 0.31% estimated exploitation activity in the next 30 days; percentile 24.14 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Users with the ability to commit changes to a repository that uses TechDocs can circumvent the MkDocs configuration file sanitizer introduced in response to CVE-2026-25153 and execute arbitrary code on the TechDocs backend host during documentation generation. Patches Patched in@backstage/plugin-techdocs-node version 1.15.4 Workarounds If you cannot upgrade immediately: - Use Docker mode with restricted access: Configure TechDocs with runIn: docker instead of runIn: local. This provides container isolation, though it does not fully mitigate the risk. - Limit repository write access to trusted parties, since exploitation requires the ability to commit files to a repository with TechDocs enabled. - Review incoming changes to MkDocs configuration files as part of your code review process.

Published by the source

7 Oct 2026, 16:23 UTC

Last modified by the source

7 Oct 2026, 16:30 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-p75x-jh7p-ppcx

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-p75x-jh7p-ppcx

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-p75x-jh7p-ppcx

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# Patch Next advisory brief: CVE-2026-106505

Advisory: Backstage: Bypass of MkDocs configuration sanitizer in TechDocs backend
IDs: CVE-2026-106505, GHSA-p75x-jh7p-ppcx
Record: https://patchnext.com/advisories/cve-2026-106505 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @backstage/plugin-techdocs-node 1.15.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/plugin-techdocs-node: affected < 1.15.4; fixed in 1.15.4

## Suggested inspection (read-only)
- `npm ls @backstage/plugin-techdocs-node --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @backstage/plugin-techdocs-node.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-p75x-jh7p-ppcx (GitHub-reviewed advisory GHSA-p75x-jh7p-ppcx lists affected ranges: npm @backstage/plugin-techdocs-node >=0 <1.15.4)
- Verified: https://osv.dev/vulnerability/GHSA-p75x-jh7p-ppcx (OSV record GHSA-p75x-jh7p-ppcx lists affected ranges: npm @backstage/plugin-techdocs-node >=0 <1.15.4 (fixed))

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