CVE-2026-106503
Backstage: Scaffolder action input authorization bypass
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.
INFO
Published Date :
Oct. 6, 2026, 10:17 p.m.
Last Modified :
Oct. 13, 2026, 2:37 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-106503
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update @backstage/plugin-scaffolder-backend to version 3.3.1 or later.
- Update to version 3.4.1, 4.0.3, or 4.1.0.
- Verify Scaffolder template action restrictions.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-106503.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-106503 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-106503
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-106503 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-106503 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Oct. 13, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:linuxfoundation:backstage/plugin-scaffolder-backend:*:*:*:*:*:*:*:* versions up to (excluding) 3.3.1 *cpe:2.3:a:linuxfoundation:backstage/plugin-scaffolder-backend:*:*:*:*:*:*:*:* versions from (including) 3.4.0 up to (excluding) 3.4.1 *cpe:2.3:a:linuxfoundation:backstage/plugin-scaffolder-backend:*:*:*:*:*:*:*:* versions from (including) 4.0.0 up to (excluding) 4.0.3 *cpe:2.3:a:linuxfoundation:backstage/plugin-scaffolder-backend:*:*:*:*:*:*:*:* versions from (including) 4.0.4 up to (excluding) 4.1.0 Added CPE Configuration OR *cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:* versions up to (excluding) 1.49.6 *cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:* versions from (including) 1.50.0 up to (excluding) 1.50.5 *cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:* versions from (including) 1.51.0 up to (excluding) 1.54.6 Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/commit/11c1384c0649b8ab26391c6a4e4f34b80ab0d188 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/commit/a91ed72d540e80b62a73b39bb1563ff5018d52d1 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/commit/e307e4f487103d815e484291b3fda778ab9983bf Types: Patch Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/releases/tag/v1.49.6 Types: Patch, Release Notes Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/releases/tag/v1.50.5 Types: Patch, Release Notes Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/releases/tag/v1.54.6 Types: Patch, Release Notes Added Reference Type GitHub, Inc.: https://github.com/backstage/backstage/security/advisories/GHSA-hmp2-4m7g-22cv Types: Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Oct. 09, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-106503', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-10-09T01:55:45.447568Z'} -
New CVE Received by [email protected]
Oct. 06, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-284 Added CWE CWE-178 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/106xxx/CVE-2026-106503.json">CVE-2026-106503</a> Added Reference https://github.com/backstage/backstage/commit/11c1384c0649b8ab26391c6a4e4f34b80ab0d188 Added Reference https://github.com/backstage/backstage/commit/a91ed72d540e80b62a73b39bb1563ff5018d52d1 Added Reference https://github.com/backstage/backstage/commit/e307e4f487103d815e484291b3fda778ab9983bf Added Reference https://github.com/backstage/backstage/releases/tag/v1.49.6 Added Reference https://github.com/backstage/backstage/releases/tag/v1.50.5 Added Reference https://github.com/backstage/backstage/releases/tag/v1.54.6 Added Reference https://github.com/backstage/backstage/security/advisories/GHSA-hmp2-4m7g-22cv