Vulnerability in @backstage/plugin-proxy-backend (CVE-2026-106491)
Summary
Vulnerability in @backstage/plugin-proxy-backend (CVE-2026-106491). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 0.6.17 or later.
Original description
The description as published by the source.
Impact
An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default.
Patches
Patched in @backstage/plugin-proxy-backend version 0.6.17
Workarounds
- Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend.
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-2026-106491 has been found in @backstage/plugin-proxy-backend.
Risk of unauthorized operations or information disclosure. CVSS score: 6.4/10.
What to do: upgrade @backstage/plugin-proxy-backend to 0.6.17 or later.
If unsure, ask your IT team or search "@backstage/plugin-proxy-backend CVE-2026-106491" on the vendor's site.
CVE-2026-106491 (@backstage/plugin-proxy-backend) — CWE-20 / CVSS v3 6.4
Attack vector: remote (network-reachable) / no user interaction
Patched: 0.6.17 — apply immediately
Workaround: - Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend.
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-20) exists in @backstage/plugin-proxy-backend.
Check the vendor advisory for the affected versions of @backstage/plugin-proxy-backend.
Severity: Medium (CVSS 6.4/10). Risk of unauthorized operations or information disclosure.
Update to 0.6.17.
Workaround: - Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@backstage/plugin-proxy-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-proxy-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-proxy-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 temporary workaround mitigate
- Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend.パッチが適用されるまでの応急処置として、- Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade @backstage/plugin-proxy-backend to 0.6.17ステージング環境で 0.6.17 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。
-
4Post-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
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com