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TI-2026-69066 Aliases CVE-2026-106491GHSA-9ghw-48h5-v2w5

Path traversal in Backstage proxy-backend

Priority LOW 28CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Backstage, an open framework for developer portals, has improper input validation in the @backstage/plugin-proxy-backend package before 0.6.17. A crafted request URL makes the proxy forward requests to a path outside the configured base path on the target server (CWE-22). An authenticated Backstage user with low privileges can trigger it, but only against target servers already configured as proxy endpoints.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. 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. This issue is fixed in version 0.6.17.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00275 19th percentileScored 2026-11-07
Fix Partial backstage (backstage): 1.54.6plugin-proxy-backend (@backstage): 0.6.17+1 more productRed Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
backstagebackstagebefore 1.54.61.54.6Patch availableCNA
backstageplugin-proxy-backendbefore 0.6.170.6.17Patch availableCNA
—@backstage/plugin-proxy-backend (npm)before 0.6.170.6.17Patch availableGHSA-9ghw-48h5-v2w5
  • backstage Vendorbackstage Affected before 1.54.6 Fixed in 1.54.6 Patch available CNA
  • plugin-proxy-backend Vendorbackstage Affected before 0.6.17 Fixed in 0.6.17 Patch available CNA
  • @backstage/plugin-proxy-backend (npm) Vendor— Affected before 0.6.17 Fixed in 0.6.17 Patch available GHSA-9ghw-48h5-v2w5

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:linuxfoundation:backstage\/plugin-proxy-backend:*:*:*:*:*:node.js:*:*before 0.6.17Vulnerablebackstage
cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:*before 1.54.6Vulnerablebackstage
  • cpe:2.3:a:linuxfoundation:backstage\/plugin-proxy-backend:*:*:*:*:*:node.js:*:* Versions before 0.6.17 Vulnerable ·backstage
  • cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:* Versions before 1.54.6 Vulnerable ·backstage

Remediation

Update @backstage/plugin-proxy-backend to version 0.6.17, which fixes the flaw. The sources list no fixed version for backstage. Red Hat rates this Moderate and lists Red Hat Developer Hub 1 and Self-service automation portal 2 as affected without a fix, with no plan available.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA backstage (backstage) Fixed in 1.54.6
  • Fix · CNA plugin-proxy-backend (@backstage) Fixed in 0.6.17
  • Fix · GHSA-9ghw-48h5-v2w5 @backstage/plugin-proxy-backend (npm) Fixed in 0.6.17 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Developer Hub 1AffectedNo fix yet: Fix deferred
Self-service automation portal 2AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-07 Threatist record created from CVE-2026-106491
  2. 2026-10-07 CISA SSVC decision points changed
  3. 2026-10-07 Priority changed: MEDIUM → LOW
  4. 2026-10-07 Alias added: GHSA-9ghw-48h5-v2w5
  5. 2026-10-07 Fix available: npm/@backstage/[email protected] · GHSA-9ghw-48h5-v2w5
  6. 2026-10-07 CVSS score added · GHSA-9ghw-48h5-v2w5
  7. 2026-10-07 Weakness changed · GHSA-9ghw-48h5-v2w5
  8. 2026-10-07 5 new references · GHSA-9ghw-48h5-v2w5
  9. 2026-10-09 Affected versions changed · Red Hat
  10. 2026-10-09 CVSS score added · Red Hat
  11. 2026-10-27 Affected versions changed · Red Hat

References

Patch 2

Advisory 2

Other 1

  • TI-2023-17988 Insecure sandbox in Backstage Scaffolder plugin CVSS 3.1CRITICAL 9.9
  • TI-2026-69075 Sensitive information exposure in Backstage Scaffolder CVSS 3.1CRITICAL 9.6
  • TI-2026-69061 Path traversal in Backstage Bitbucket pull-request scaffolder actions CVSS 3.1CRITICAL 9.9
  • TI-2026-60083 Backstage: Improper input validation in TechDocs MkDocs configuration CVSS 3.1HIGH 8.8
  • TI-2026-69165 Backstage TechDocs config flaw allows code execution CVSS 3.1HIGH 8.8
  • TI-2026-69083 Code injection via MkDocs theme configuration in Backstage TechDocs CVSS 3.1HIGH 8.8
See all 52 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences