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Backstage has a Possible Symlink Path Traversal in Scaffolder Actions

High severity GitHub Reviewed Published Jan 21, 2026 in backstage/backstage • Updated Jan 22, 2026

Package

npm @backstage/backend-defaults (npm)

Affected versions

< 0.12.2
>= 0.13.0, < 0.13.2
>= 0.14.0, < 0.14.1

Patched versions

0.12.2
0.13.2
0.14.1
npm @backstage/plugin-scaffolder-backend (npm)
< 2.2.2
>= 3.0.0, < 3.0.2
>= 3.1.0, < 3.1.1
2.2.2
3.0.2
3.1.1
npm @backstage/plugin-scaffolder-node (npm)
< 0.11.2
>= 0.12.0, < 0.12.3
0.11.2
0.12.3

Description

Impact

Multiple Scaffolder actions and archive extraction utilities were vulnerable to symlink-based path traversal attacks. An attacker with access to create and execute Scaffolder templates could exploit symlinks to:

  1. Read arbitrary files via the debug:log action by creating a symlink pointing to sensitive files (e.g., /etc/passwd, configuration files, secrets)
  2. Delete arbitrary files via the fs:delete action by creating symlinks pointing outside the workspace
  3. Write files outside the workspace via archive extraction (tar/zip) containing malicious symlinks

This affects any Backstage deployment where users can create or execute Scaffolder templates.

Patches

This vulnerability is fixed in the following package versions:

  • @backstage/backend-defaults version 0.12.2, 0.13.2, 0.14.1, 0.15.0
  • @backstage/plugin-scaffolder-backend version 2.2.2, 3.0.2, 3.1.1
  • @backstage/plugin-scaffolder-node version 0.11.2, 0.12.3

Users should upgrade to these versions or later.

Workarounds

  • Follow the recommendation in the Backstage Threat Model to limit access to creating and updating templates
  • Restrict who can create and execute Scaffolder templates using the permissions framework
  • Audit existing templates for symlink usage
  • Run Backstage in a containerized environment with limited filesystem access

References

References

@Rugvip Rugvip published to backstage/backstage Jan 21, 2026
Published to the GitHub Advisory Database Jan 21, 2026
Reviewed Jan 21, 2026
Published by the National Vulnerability Database Jan 21, 2026
Last updated Jan 22, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:L

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(3rd percentile)

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

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. Learn more on MITRE.

CVE ID

CVE-2026-24046

GHSA ID

GHSA-rq6q-wr2q-7pgp

Source code

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