CVE-2026-106503

HIGH

8.1

CVSS v3

Description

Backstage is an open framework for building developer portals. Prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by scaffolder action input authorization bypass. An authenticated user with access to affected Scaffolder templates could bypass configured action restrictions. Depending on integration credentials, this could grant unauthorized access to repositories and related source-control resources. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.

CWE-178 CWE-284Improper Access Control

How to fix

Remediation Available

@backstage/plugin-scaffolder-backendnpm

Fixed in:3.3.1GHSA-hmp2-4m7g-22cv

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Exploit Intelligence

0.49%probability of exploitation in 30 days

42ndpercentile

Moderate risk: more likely to be exploited than 42% of all known CVEs.

References

Patch6

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-178 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-27636	Medium	5.6	97%	-	Fix
CVE-2021-24347	High	8.8	54%	-	Fix
CVE-2020-12812	Critical	9.8	45%	KEV + Ransom	Fix
CVE-2003-0411	High	7.5	25%	-	-
CVE-2026-47323	Critical	9.8	20%	-	Fix
CVE-2018-9845	Critical	9.8	13%	-	Fix

Common questions

How do I fix CVE-2026-106503?

Upgrade @backstage/plugin-scaffolder-backend to 3.3.1 or later.

Is CVE-2026-106503 being actively exploited?

Not that we know of. CVE-2026-106503 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.49% is the estimated probability that it will be exploited in the next 30 days. That is higher than 42% of all scored CVEs.

How severe is CVE-2026-106503?

CVE-2026-106503 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-106503 affect?

Published advisories record a fix for @backstage/plugin-scaffolder-backend (npm). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-106503

Markdown

[![CVE-2026-106503](https://tridentstack.com/cve/badge/CVE-2026-106503.svg)](https://tridentstack.com/cve/CVE-2026-106503)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-106503"><img src="https://tridentstack.com/cve/badge/CVE-2026-106503.svg" alt="CVE-2026-106503"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Run a free CVE scan on your fleet Start freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-13.