Vulnerability in @backstage/plugin-scaffolder-backend (CVE-2026-106499)
Summary
Vulnerability in @backstage/plugin-scaffolder-backend (CVE-2026-106499). Confidential information can be exposed externally. Exploitable via scaffolder.defaultEnvironment.secrets. Mitigation: upgrade to 4.1.0 or later.
Original description
The description as published by the source.
Impact
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 in task logs, exposing those values to users with access to the resulting task logs.
Patches
Patched in @backstage/plugin-scaffolder-backend version 4.1.0
Workarounds
- Restrict permission to create or update Template entities to fully trusted parties, as recommended by the Backstage threat model.
- If that restriction cannot be guaranteed, remove sensitive values from
scaffolder.defaultEnvironment.secretsuntil a patched version is available.
No complete workaround is known that preserves both untrusted template authoring and access to sensitive default-environment secrets.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-106499 has been found in @backstage/plugin-scaffolder-backend.
Attackers can target a specific entry point like scaffolder.defaultEnvironment.secrets over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 4.9/10.
What to do: upgrade @backstage/plugin-scaffolder-backend to 4.1.0 or later.
If unsure, ask your IT team or search "@backstage/plugin-scaffolder-backend CVE-2026-106499" on the vendor's site.
CVE-2026-106499 (@backstage/plugin-scaffolder-backend) — CWE-532 / CVSS v3 4.9
Attack vector: remote (network-reachable) / no user interaction
Attack surface: scaffolder.defaultEnvironment.secrets
Patched: 4.1.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-532) exists in @backstage/plugin-scaffolder-backend. Attackers reach the vulnerable code path via scaffolder.defaultEnvironment.secrets.
Check the vendor advisory for the affected versions of @backstage/plugin-scaffolder-backend. Attack surface: scaffolder.defaultEnvironment.secrets.
Severity: Medium (CVSS 4.9/10). Confidential information can be exposed externally.
Update to 4.1.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@backstage/plugin-scaffolder-backend' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r '@backstage/plugin-scaffolder-backend' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
@backstage/plugin-scaffolder-backendを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @backstage/plugin-scaffolder-backend to 4.1.0ステージング環境で 4.1.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- patch security-advisories@github.com
- patch security-advisories@github.com
- patch security-advisories@github.com
- web nvd.nist.gov
- web github.com