Vulnerabilities in pkg:npm/@backstage/plugin-techdocs-node

PACKAGE
Advisory Identifier: GHSA-q38j-6vcm-2f5m
Advisory Summary

CVE-2026-106455 is a HIGH (CVSS 7.7) improper validation of mkdocs plugin vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting Backstage libraries in the npm ecosystem. The issue involves improper validation of mkdocs plugin configuration in techdocs. Remediation is available by upgrading affected packages to version 1.14.7, 1.15.5.

11 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/@backstage/plugin-techdocs-node

11 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/@backstage/plugin-techdocs-node. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-q38j-6vcm-2f5m CVE-2026-106455 HIGH Backstage: Improper validation of MkDocs plugin configuration in TechDocs
GHSA-4488-j8vj-vqqv CVE-2026-106510 HIGH Backstage: Remote code execution via crafted markdown_extensions in TechDocs mkdocs.yml
GHSA-qmw3-745m-w99g CVE-2026-106558 HIGH Backstage: Improper validation of TechDocs MkDocs configuration
GHSA-p75x-jh7p-ppcx CVE-2026-106505 HIGH Backstage: Bypass of MkDocs configuration sanitizer in TechDocs backend
GHSA-cm77-ch27-6w6v CVE-2026-106508 MODERATE Backstage has potential file exposure through local TechDocs publisher
GHSA-8w7q-29mw-gf5c CVE-2026-106509 HIGH Backstage: Improper validation of MkDocs theme configuration in TechDocs
GHSA-f7v3-xhm6-w245 CVE-2026-106557 HIGH Backstage has improper input validation in TechDocs Markdown extension configuration
GHSA-928r-fm4v-mvrw CVE-2026-29186 HIGH TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution
GHSA-6jr7-99pf-8vgf CVE-2026-25153 HIGH @backstage/plugin-techdocs-node vulnerable to arbitrary code execution via MkDocs hooks
GHSA-w669-jj7h-88m9 CVE-2026-25152 MODERATE @backstage/plugin-techdocs-node vulnerable to possible Path Traversal in TechDocs Local Generator
GHSA-4jqc-jvh2-pxg9 - MODERATE Path traversal for local publishers in TechDocs backend

CVE-2026-106455 at a Glance

CVE Identifier CVE-2026-106455
GHSA Identifier GHSA-q38j-6vcm-2f5m
Severity HIGH
CVSS v3.1 Base Score 7.7
CWE Classification CWE-918: Server-Side Request Forgery (SSRF)
Affected Product Backstage
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.7

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-106455

To remediate this vulnerability, upgrade all affected Backstage dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@backstage/plugin-techdocs-node fixed: 1.14.7
npm install @backstage/plugin-techdocs-node@1.14.7
@backstage/plugin-techdocs-node fixed: 1.15.5
npm install @backstage/plugin-techdocs-node@1.15.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

npm ls @backstage/plugin-techdocs-node

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-106455, inspect your project dependencies using npm:

npm ls @backstage/plugin-techdocs-node

Analyze the terminal output to locate any version of Backstage in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.14.7), your application is affected.

Note: The npm ls @backstage/plugin-techdocs-node command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. In Backstage, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact An authenticated attacker with control over a TechDocs source repository could cause a documentation build to retrieve and publish data from network locations reachable by the build environment. Exposure depends on deployment topology, build mode, and target endpoint protections. Modern cloud metadata services that require tokens or special headers are not directly accessible through the affected behavior. ### Patches Upgrade `@backstage/plugin-techdocs-node` to a patched version for the applicable release line: - `1.14.x`: upgrade to `1.14.7` or later in that line, available in [Backstage v1.50.6](https://github.com/backstage/backstage/releases/tag/v1.50.6). - `1.15.x`: upgrade to `1.15.5` or later, available in [Backstage v1.54.8](https://github.com/backstage/backstage/releases/tag/v1.54.8). - Current mainline: upgrade to `2.0.0` or later, available in [Backstage v1.55.0](https://github.com/backstage/backstage/releases/tag/v1.55.0). The update removes MkDocs plugins outside the built-in allowlist. To retain additional plugins, review them and configure `techdocs.generator.mkdocs.dangerouslyAllowAdditionalPlugins`, or supply `dangerouslyAllowAdditionalPlugins` when creating the generator directly. Plugins supplied through `defaultPlugins` remain permitted. ### Workarounds - Restrict control of TechDocs source repositories and catalog registration to trusted maintainers. - Run documentation builders with outbound access to private and link-local networks denied. - Require token- or header-protected cloud instance metadata services.

CVE-2026-106455 Affected Backstage Versions

2 component(s)
Fixed Versions:
1.14.71.15.5
Product / Package Ecosystem Affected Versions Fixed Version
@backstage/plugin-techdocs-node
npm
≥ 0.11.12
< 1.14.7
1.14.7
@backstage/plugin-techdocs-node
npm
≥ 1.15.0
< 1.15.5
1.15.5

References

Frequently Asked Questions

What is CVE-2026-106455?
CVE-2026-106455 is a security vulnerability in Backstage involving Improper validation of MkDocs plugin configuration in TechDocs under CWE-918: Server-Side Request Forgery (SSRF).
Which Backstage versions are affected?
Affected versions include releases prior to 1.14.7, 1.15.5 across affected packages: @backstage/plugin-techdocs-node.
What version fixes CVE-2026-106455?
Upgrading to 1.14.7, 1.15.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @backstage/plugin-techdocs-node affected?
Yes, @backstage/plugin-techdocs-node is affected in releases prior to 1.14.7, 1.15.5. Upgrade your dependency to 1.14.7, 1.15.5 or later.
What is the CVSS score of CVE-2026-106455?
CVE-2026-106455 has a CVSS v3.1 base score of 7.7 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N.
What CWE is associated with CVE-2026-106455?
CVE-2026-106455 is classified under CWE-918: Server-Side Request Forgery (SSRF) (The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.).
How can I check npm dependencies for CVE-2026-106455?
Run the dependency tree command: 'npm ls @backstage/plugin-techdocs-node'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q38j-6vcm-2f5m",
  "modified" : "2026-10-07T20:25:19Z",
  "published" : "2026-10-07T20:25:19Z",
  "aliases" : [ "CVE-2026-106455" ],
  "summary" : "Backstage: Improper validation of MkDocs plugin configuration in TechDocs",
  "details" : "### Impact\n\nAn authenticated attacker with control over a TechDocs source repository could cause a documentation build to retrieve and publish data from network locations reachable by the build environment. Exposure depends on deployment topology, build mode, and target endpoint protections. Modern cloud metadata services that require tokens or special headers are not directly accessible through the affected behavior.\n\n### Patches\n\nUpgrade `@backstage/plugin-techdocs-node` to a patched version for the applicable release line:\n\n- `1.14.x`: upgrade to `1.14.7` or later in that line, available in [Backstage v1.50.6](https://github.com/backstage/backstage/releases/tag/v1.50.6).\n- `1.15.x`: upgrade to `1.15.5` or later, available in [Backstage v1.54.8](https://github.com/backstage/backstage/releases/tag/v1.54.8).\n- Current mainline: upgrade to `2.0.0` or later, available in [Backstage v1.55.0](https://github.com/backstage/backstage/releases/tag/v1.55.0).\n\nThe update removes MkDocs plugins outside the built-in allowlist. To retain additional plugins, review them and configure `techdocs.generator.mkdocs.dangerouslyAllowAdditionalPlugins`, or supply `dangerouslyAllowAdditionalPlugins` when creating the generator directly. Plugins supplied through `defaultPlugins` remain permitted.\n\n### Workarounds\n\n- Restrict control of TechDocs source repositories and catalog registration to trusted maintainers.\n- Run documentation builders with outbound access to private and link-local networks denied.\n- Require token- or header-protected cloud instance metadata services.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-techdocs-node"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.11.12"
      }, {
        "fixed" : "1.14.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/plugin-techdocs-node"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.15.0"
      }, {
        "fixed" : "1.15.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/security/advisories/GHSA-q38j-6vcm-2f5m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-106455"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/28aa82ae2815988721dd7bbf43cd69c431dcd71b"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/9f76ea445088961f68c364764cc4b7734f368fc0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/backstage/backstage"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/releases/tag/v1.50.6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/releases/tag/v1.54.8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/releases/tag/v1.55.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-07T20:25:19Z",
    "nvd_published_at" : "2026-10-06T21:17:15Z"
  }
}