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vulnerability / NVI-00012053 / Revision 3

Backstage has improper input validation in TechDocs Markdown extension configuration

GitHub lists this reviewed advisory for @backstage/plugin-techdocs-node. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.

source listedactiveGHSA-f7v3-xhm6-w245CVE-2026-106557

This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.

01 / Meaning

Why it matters

Published affected context helps an owner decide what evidence to gather. This report has not examined your application.

CVSS

7.7 high

GitHub source severity; exploitability and local consequence require separate evidence.

As of · GitHub Advisory Database

EPSS

0.375%

FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.31467. Missing scores are unknown.

As of · FIRST EPSS

02 / Applicability

The affected context

Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.

@backstage/plugin-techdocs-node

source listed
  • < 1.15.4

### Impact An 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. ### Patches Patched in `@backstage/plugin-techdocs-node` version `1.15.4`. Adopters 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. ### Workarounds - Generate TechDocs only from trusted repositories with reviewed MkDocs configuration. - Use isolated build environments with restricted filesystem access and network egress. - Prefer externally generated TechDocs with appropriately sandboxed CI.

GitHub Advisory Database

03 / Response

What to do next

  1. investigate

    Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.

    Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS

A fixed release is not deployment evidence.

Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.

04 / Limits

What this report cannot establish

  • Customer inventory, deployment, reachability and exploitation have not been inspected.
Read the collection and interpretation limits ↗

05 / Provenance

Sources you can inspect

Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.

  1. GHSA-f7v3-xhm6-w245 ↗

    GitHub Advisory Database · vendor advisory

    Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.

  2. CVE-2026-106557 ↗

    FIRST EPSS · official catalog

    Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.

Public revision history

Only published revisions appear here. Routine fetches do not create a material-change event.

  1. Revision 3 ·

    Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.

  2. Revision 2 ·

    Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.

  3. Revision 1 ·

    First indexed by Null; source disclosure date is shown separately.

Read the public revision data ↗

The next step is private

Bring the question into your environment.

The connected workflow is a development preview for inventory, contextual matching, owner decisions and evidence-based verification. No system-specific result is generated by this page.

See the synthetic workflow preview ↗