GHSA-8qp7-fhr9-fw53 CVE-2026-29184
@backstage/plugin-scaffolder-backend Vulnerable to Potential Session Token Exfiltration via Log Redaction Bypass
Medium
npm
- Severity
- 2.0 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.28%
- Chance of exploitation in the next 30 days. Higher than 20.26% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-532 Insertion of Sensitive Information into Log File
- Fix
3.1.4- Upgrade @backstage/plugin-scaffolder-backend to this version or later
Description
Impact
A malicious scaffolder template can bypass the log redaction mechanism to exfiltrate secrets provided run through task event logs.
The attack requires:
- The ability to register a template in the catalog
- A victim who executes the malicious template
Patches
Patched in @backstage/plugin-scaffolder-backend version 3.1.4
Workarounds
- Implement a custom permission policy that restricts scaffolder.task.read so users can only read their own task logs
- Restrict who can register templates in the catalog to trusted users only
Resources
- Backstage Scaffolder permissions documentation: https://backstage.io/docs/permissions/plugin-authors/01-setup/
- Backstage Threat Model: https://backstage.io/docs/overview/threat-model/
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| @backstage/plugin-scaffolder-backend | < 3.1.4 |
3.1.4 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
@backstage/plugin-scaffolder-backend npm → 3.1.4
- npm
npm install @backstage/plugin-scaffolder-backend@3.1.4- yarn
yarn add @backstage/plugin-scaffolder-backend@3.1.4- pnpm
pnpm add @backstage/plugin-scaffolder-backend@3.1.4
Severity breakdown
CVSS 3.1 2.0
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- High
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-532: Insertion of Sensitive Information into Log File
The product writes sensitive information to a log file.
How to prevent it
- Architecture and Design, Implementation: Consider seriously the sensitivity of the information written into log files. Do not write secrets into the log files.
- Distribution: Remove debug log files before deploying the application into production.
- Operation: Protect log files against unauthorized read/write.
- Implementation: Adjust configurations appropriately when software is transitioned from a debug state to production.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-vwp5-f99x-x3rq Backstage has improper input validation in scaffolder task list ordering | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-4xvq-3m68-h444 Backstage has sensitive information exposure in scaffolder task logs | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-hmp2-4m7g-22cv Backstage: Scaffolder action input authorization bypass | High | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-95p4-vv4g-jxxm Backstage may expose sensitive information in Scaffolder task failure events | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-g2v8-7jhw-pp8p Backstage: Sensitive information exposure in Scaffolder | Critical | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-xvgh-hmx8-9xxf Backstage: Improper task state validation in Scaffolder backend | High | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-mfvq-x7vr-rgqg Backstage: Secret-derived values may be exposed in scaffolder task logs | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-29gx-h2m3-xw44 Backstage's scaffolder credential handling may allow unintended GitHub authentication fallback | Medium | Also affects @backstage/plugin-scaffolder-backend |
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