Backstage is an open framework for building developer portals. From 0.5.0 until 0.6.18, the @backstage/plugin-proxy-backend package is affected by inconsistent credential enforcement for overlapping proxy routes. An operator can configure overlapping proxy paths with different credential requirements. When a parent path permits unauthenticated access and a nested path requires credentials, the parent exemption can also cover requests handled by the nested proxy. An unauthenticated caller may therefore reach the nested upstream through Backstage, including with static upstream credentials configured for that proxy. This issue is fixed in version 0.6.18.
CVE-2026-106456
MEDIUMPre-NVD 4.84.8
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 4.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
4.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 4.8Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 4.8
- EG Score
- 4.8MEDIUMlow confidence
- EG Risk
- 22EG Risk 22/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity48% × 45%Exploitation0% × 40%Automatability0% × 15%CISA SSVC: Track at every mission impact level.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
CISA SSVCTrack at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 6, 2026
Last Modified
October 7, 2026
Advisory Details (3)
Auto-updated Oct 6, 2026Patch available. Sources: github_commit, github_release, github.
github_release Patch Available
v1.55.0
Patch available: backstage/backstage v1.55.0
https://github.com/backstage/backstage/releases/tag/v1.55.0github_commit Patch Available
commit 9df92923ac32 (backstage/backstage)
Patch available: backstage/backstage v1.55.0 (contains commit 9df92923ac32)
https://github.com/backstage/backstage/commit/9df92923ac32558bb80edeceafd8de780c44e218githubMentions a patch (unverified)
Inconsistent credential enforcement for overlapping proxy routes · Advisory · backstage/backstage · GitHub
https://github.com/backstage/backstage/security/advisories/GHSA-472h-9c5j-prrrVendor Advisories for CVE-2026-106456(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-10-07 19:19 UTCEG score recompute
- 2026-10-07 18:28 UTCEG score recompute
- 2026-10-06 21:32 UTCEG score recompute
- 2026-10-06 20:22 UTCEG score recompute
- 2026-10-06 20:22 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-106456?
CVE-2026-106456 is a medium vulnerability published on October 6, 2026. Backstage is an open framework for building developer portals. From 0.5.0 until 0.6.18, the @backstage/plugin-proxy-backend package is affected by inconsistent credential enforcement for overlapping proxy routes. An operator can configure overlapping proxy paths with different credential…
When was CVE-2026-106456 disclosed?
CVE-2026-106456 was first published on October 6, 2026, with the most recent update on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-106456?
CVE-2026-106456 has a CVSS base score of 4.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-106456?
A fix for CVE-2026-106456 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-106456 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-106456
Is Your Infrastructure Affected by CVE-2026-106456?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.