CVE-2026-24047: @backstage/cli common @backstage/cli-common Has A Possible `resolveSafeChildPath` Vulnerability

MODERATE
Advisory Identifier: GHSA-2p49-45hj-7mc9
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CVSS 6.3
CWE-59 CWE-61
Published
Advisory Summary

CVE-2026-24047 is a MODERATE (CVSS 6.3) @backstage/cli-common has a possible `resolvesafechildpath` vulnerability (CWE-59: Improper Link Resolution Before File Access ('Link Following')) affecting @backstage/cli common libraries in the npm ecosystem. The issue involves @backstage/cli-common has a possible `resolvesafechildpath` symlink chain bypass. Remediation is available by upgrading affected packages to version 0.1.17.

CVE-2026-24047 at a Glance

CVE Identifier CVE-2026-24047
GHSA Identifier GHSA-2p49-45hj-7mc9
Severity MODERATE
CVSS v3.1 Base Score 6.3
CWE Classification CWE-59: Improper Link Resolution Before File Access ('Link Following')
Affected Product @backstage/cli common
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.3

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

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
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-2026-24047

To remediate this vulnerability, upgrade all affected @backstage/cli common 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/cli-common fixed: 0.1.17 
npm install @backstage/cli-common@0.1.17
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/cli-common

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-24047, inspect your project dependencies using npm:

npm ls @backstage/cli-common

Analyze the terminal output to locate any version of @backstage/cli common in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.1.17), your application is affected.

Note: The npm ls @backstage/cli-common 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-59: Improper Link Resolution Before File Access ('Link Following'), where the product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. In @backstage/cli common, 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 The `resolveSafeChildPath` utility function in `@backstage/backend-plugin-api`, which is used to prevent path traversal attacks, failed to properly validate symlink chains and dangling symlinks. An attacker could bypass the path validation by: 1. **Symlink chains**: Creating `link1 → link2 → /outside` where intermediate symlinks eventually resolve outside the allowed directory 2. **Dangling symlinks**: Creating symlinks pointing to non-existent paths outside the base directory, which would later be created during file operations This function is used by Scaffolder actions and other backend components to ensure file operations stay within designated directories. ### Patches This vulnerability is fixed in `@backstage/backend-plugin-api` version 0.1.17. Users should upgrade to this version or later. ### Workarounds - Run Backstage in a containerised environment with limited filesystem access - Restrict template creation to trusted users

CVE-2026-24047 Affected @backstage/cli common Versions

1 component(s)
Fixed Versions:
0.1.17
Product / Package Ecosystem Affected Versions Fixed Version
@backstage/cli-common
npm/@backstage/cli-common
npm
< 0.1.17
0.1.17

References

GitHub Advisory / Wiki ADVISORY
https://github.com/backstage/backstage/security/advisories/GHSA-2p49-45hj-7mc9
NVD — CVE-2026-24047 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-24047
Security Fix Commit FIX COMMIT
https://github.com/backstage/backstage/commit/ae4dd5d1572a4f639e1a466fd982656b50f8e692
@backstage/cli common Source Repository REPOSITORY
https://github.com/backstage/backstage

Frequently Asked Questions

What is CVE-2026-24047?
CVE-2026-24047 is a security vulnerability in @backstage/cli common involving @backstage/cli-common has a possible `resolveSafeChildPath` Symlink Chain Bypass under CWE-59: Improper Link Resolution Before File Access ('Link Following').
Which @backstage/cli common versions are affected?
Affected versions include releases prior to 0.1.17 across affected packages: @backstage/cli-common.
What version fixes CVE-2026-24047?
Upgrading to 0.1.17 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @backstage/cli-common affected?
Yes, @backstage/cli-common is affected in releases prior to 0.1.17. Upgrade your dependency to 0.1.17 or later.
What is the CVSS score of CVE-2026-24047?
CVE-2026-24047 has a CVSS v3.1 base score of 6.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N.
What CWE is associated with CVE-2026-24047?
CVE-2026-24047 is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following') (The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.).
How can I check npm dependencies for CVE-2026-24047?
Run the dependency tree command: 'npm ls @backstage/cli-common'. 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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2p49-45hj-7mc9",
  "modified" : "2026-01-22T15:41:11Z",
  "published" : "2026-01-21T22:40:51Z",
  "aliases" : [ "CVE-2026-24047" ],
  "summary" : "@backstage/cli-common has a possible `resolveSafeChildPath` Symlink Chain Bypass",
  "details" : "### Impact\n\nThe `resolveSafeChildPath` utility function in `@backstage/backend-plugin-api`, which is used to prevent path traversal attacks, failed to properly validate symlink chains and dangling symlinks. An attacker could bypass the path validation by:\n\n1. **Symlink chains**: Creating `link1 → link2 → /outside` where intermediate symlinks eventually resolve outside the allowed directory\n2. **Dangling symlinks**: Creating symlinks pointing to non-existent paths outside the base directory, which would later be created during file operations\n\nThis function is used by Scaffolder actions and other backend components to ensure file operations stay within designated directories.\n\n### Patches\n\nThis vulnerability is fixed in `@backstage/backend-plugin-api` version 0.1.17. Users should upgrade to this version or later.\n\n### Workarounds\n\n- Run Backstage in a containerised environment with limited filesystem access\n- Restrict template creation to trusted users",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@backstage/cli-common"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.1.17"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.1.16"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/security/advisories/GHSA-2p49-45hj-7mc9"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24047"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/backstage/backstage/commit/ae4dd5d1572a4f639e1a466fd982656b50f8e692"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/backstage/backstage"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59", "CWE-61" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-21T22:40:51Z",
    "nvd_published_at" : "2026-01-21T23:15:53Z"
  }
}