Backstage vulnerabilities

72 vulnerabilities

Known vulnerabilities in Backstage products, newest first, with CVSS severity, EPSS, KEV listings and ransomware use, across 28 products.

Products

28
4.3CVE-2026-106495@backstagebackend-defaults+2
EPSS score
0.24%
Backstage is an open framework for building developer portals. Prior to 0.17.8, the @backstage/backend-defaults package is affected by improper access control in backend action invocation. An authenticated user could invoke actions that an operator had excluded through action configuration. Existing action permissions and downstream authorization remain enforced. This issue is fixed in version 0.17.8.6.8CVE-2021-41151backstagebackstage+2
EPSS score
1.31%
Backstage is an open platform for building developer portals. In affected versions A malicious actor could read sensitive files from the environment where Scaffolder Tasks are run. The attack is executed by crafting a custom Scaffolder template with a `github:publish:pull-request` action and a particular source path. When the template is executed the sensitive files would be included in the published pull request. This vulnerability is mitigated by the fact that an attacker would need access to create and register templates in the Backstage catalog, and that the attack is very visible given that the exfiltration happens via a pull request. The vulnerability is patched in the `0.15.9` release of `@backstage/plugin-scaffolder-backend`.7.4CVE-2021-43776backstagebackstage+2
EPSS score
0.68%
Backstage is an open platform for building developer portals. In affected versions the auth-backend plugin allows a malicious actor to trick another user into visiting a vulnerable URL that executes an XSS attack. This attack can potentially allow the attacker to exfiltrate access tokens or other secrets from the user's browser. The default CSP does prevent this attack, but it is expected that some deployments have these policies disabled due to incompatibilities. This is vulnerability is patched in version `0.4.9` of `@backstage/plugin-auth-backend`.8.5CVE-2021-43783backstagebackstage+2
EPSS score
1.25%
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. In affected versions a malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance. This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents. This vulnerability is fixed in version `0.15.14` of the `@backstage/plugin-scaffolder-backend`. This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.8.1CVE-2021-32660backstagebackstage+2
EPSS score
1.27%
Backstage is an open platform for building developer portals, and techdocs-common contains common functionalities for Backstage's TechDocs. In versions of `@backstage/tehdocs-common` prior to 0.6.4, a malicious internal actor is able to upload documentation content with malicious scripts. These scripts would normally be sanitized by the TechDocs frontend, but by tricking a user to visit the content via the TechDocs API, the content sanitazion will be bypassed. If the TechDocs API is hosted on the same origin as the Backstage app or other backend plugins, this may give access to sensitive data. The ability to upload malicious content may be limited by internal code review processes, unless the chosen TechDocs deployment method is to use an object store and the actor has access to upload files directly to that store. The vulnerability is patched in the `0.6.4` release of `@backstage/techdocs-common`.7.3CVE-2021-32661backstagebackstage+2
EPSS score
1.21%
Backstage is an open platform for building developer portals. In versions of Backstage's Techdocs Plugin (`@backstage/plugin-techdocs`) prior to 0.9.5, a malicious internal actor can potentially upload documentation content with malicious scripts by embedding the script within an `object` element. This may give access to sensitive data when other users visit that same documentation page. The ability to upload malicious content may be limited by internal code review processes, unless the chosen TechDocs deployment method is to use an object store and the actor has access to upload files directly to that store. The vulnerability is patched in the `0.9.5` release of `@backstage/plugin-techdocs`.6.5CVE-2021-32662backstagebackstage+2
EPSS score
1.28%
Backstage is an open platform for building developer portals, and techdocs-common contains common functionalities for Backstage's TechDocs. In `@backstage/techdocs-common` versions prior to 0.6.3, a malicious actor could read sensitive files from the environment where TechDocs documentation is built and published by setting a particular path for `docs_dir` in `mkdocs.yml`. These files would then be available over the TechDocs backend API. This vulnerability is mitigated by the fact that an attacker would need access to modify the `mkdocs.yml` in the documentation source code, and would also need access to the TechDocs backend API. The vulnerability is patched in the `0.6.3` release of `@backstage/techdocs-common`.2.6CVE-2025-55285backstagebackstage+1
EPSS score
0.24%
@backstage/plugin-scaffolder-backend is the backend for the default Backstage software templates. Prior to version 2.1.1, duplicate logging of the input values in the fetch:template action in the Scaffolder meant that some of the secrets were not properly redacted. If ${{ secrets.x }} is not passed through to fetch:template there is no impact. This issue has been resolved in 2.1.1 of the scaffolder-backend plugin. A workaround for this issue involves Template Authors removing the use of ${{ secrets }} being used as an argument to fetch:template.4.3CVE-2025-32791backstagebackstage+1
EPSS score
0.29%
The Backstage Scaffolder plugin houses types and utilities for building scaffolder-related modules. A vulnerability in the Backstage permission plugin backend allows callers to extract some information about the conditional decisions returned by the permission policy installed in the permission backend. If the permission system is not in use or if the installed permission policy does not use conditional decisions, there is no impact. This issue has been patched in version 0.6.0 of the permissions backend. A workaround includes having administrators of the permission policies ensure that they are crafted in such a way that conditional decisions do not contain any sensitive information.8.7CVE-2024-26150backstagebackstage+2
EPSS score
0.80%
`@backstage/backend-common` is a common functionality library for backends for Backstage, an open platform for building developer portals. In `@backstage/backend-common` prior to versions 0.21.1, 0.20.2, and 0.19.10, paths checks with the `resolveSafeChildPath` utility were not exhaustive enough, leading to risk of path traversal vulnerabilities if symlinks can be injected by attackers. This issue is patched in `@backstage/backend-common` versions 0.21.1, 0.20.2, and 0.19.10.5.8CVE-2024-47762backstagebackstage+1
EPSS score
0.38%
Backstage is an open framework for building developer portals. Configuration supplied through APP_CONFIG_* environment variables, for example APP_CONFIG_backend_listen_port=7007, where unexpectedly ignoring the visibility defined in configuration schema. This occurred even if the configuration schema specified that they should have backend or secret visibility. This was an intended feature of the APP_CONFIG_* way of supplying configuration, but now clearly goes against the expected behavior of the configuration system. This behavior leads to a risk of potentially exposing sensitive configuration details intended to remain private or restricted to backend processes. The issue has been resolved in version 0.3.75 of the @backstage/plugin-app-backend package. As a temporary measure, avoid supplying secrets using the APP_CONFIG_ configuration pattern. Consider alternative methods for setting secrets, such as the environment substitution available for Backstage configuration.5.4CVE-2024-53983backstagebackstage+1
EPSS score
0.37%
The Backstage Scaffolder plugin Houses types and utilities for building scaffolder-related modules. A vulnerability is identified in Backstage Scaffolder template functionality where Server-Side Template Injection (SSTI) can be exploited to perform Git config injection. The vulnerability allows an attacker to capture privileged git tokens used by the Backstage Scaffolder plugin. With these tokens, unauthorized access to sensitive resources in git can be achieved. The impact is considered medium severity as the Backstage Threat Model recommends restricting access to adding and editing templates in the Backstage Catalog plugin. The issue has been resolved in versions `v0.4.12`, `v0.5.1` and `v0.6.1` of the `@backstage/plugin-scaffolder-node` package. Users are encouraged to upgrade to this version to mitigate the vulnerability. Users are advised to upgrade. Users unable to upgrade may ensure that templates do not change git config.6.5CVE-2024-46976backstagebackstage+2
EPSS score
0.29%
Backstage is an open framework for building developer portals. An attacker with control of the contents of the TechDocs storage buckets is able to inject executable scripts in the TechDocs content that will be executed in the victim's browser when browsing documentation or navigating to an attacker provided link. This has been fixed in the 1.10.13 release of the `@backstage/plugin-techdocs-backend` package. users are advised to upgrade. There are no known workarounds for this vulnerability.6.5CVE-2024-45816backstagebackstage+2
EPSS score
0.73%
Backstage is an open framework for building developer portals. When using the AWS S3 or GCS storage provider for TechDocs it is possible to access content in the entire storage bucket. This can leak contents of the bucket that are not intended to be accessible, as well as bypass permission checks in Backstage. This has been fixed in the 1.10.13 release of the `@backstage/plugin-techdocs-backend` package. All users are advised to upgrade. There are no known workarounds for this vulnerability.6.5CVE-2024-45815backstagebackstage+2
EPSS score
0.51%
Backstage is an open framework for building developer portals. A malicious actor with authenticated access to a Backstage instance with the catalog backend plugin installed is able to interrupt the service using a specially crafted query to the catalog API. This has been fixed in the `1.26.0` release of the `@backstage/plugin-catalog-backend`. All users are advised to upgrade. There are no known workarounds for this vulnerability.6.1CVE-2026-73563backstagebackstage+2
EPSS score
0.17%
Backstage is an open framework for building developer portals. Prior to 0.29.2, the experimental dynamic client registration and client ID metadata document features in the @backstage/plugin-auth-backend use full-string matcher.isMatch glob matching for auth.experimentalDynamicClientRegistration.allowedRedirectUriPatterns and the auth.experimentalClientIdMetadataDocuments allowedClientIdPatterns and allowedRedirectUriPatterns options. A hostname wildcard can match across URL component boundaries, allowing an attacker-controlled redirect URI with a trusted hostname suffix in its path to pass the allowlist and receive an OAuth authorization code after a victim completes the flow. Patterns without an explicit protocol can match unintended protocols, and redirect URIs containing embedded credentials are accepted after user information is stripped for matching. The features are experimental and disabled by default; only deployments that enable them and configure custom wildcard-hostname or protocol-less patterns are affected. This issue is first fixed in prerelease version 0.29.2.8.8CVE-2026-25153backstagebackstage+2
EPSS score
0.61%
Backstage is an open framework for building developer portals, and @backstage/plugin-techdocs-node provides common node.js functionalities for TechDocs. In versions of @backstage/plugin-techdocs-node prior to 1.13.11 and 1.14.1, when TechDocs is configured with `runIn: local`, a malicious actor who can submit or modify a repository's `mkdocs.yml` file can execute arbitrary Python code on the TechDocs build server via MkDocs hooks configuration. @backstage/plugin-techdocs-node versions 1.13.11 and 1.14.1 contain a fix. The fix introduces an allowlist of supported MkDocs configuration keys. Unsupported configuration keys (including `hooks`) are now removed from `mkdocs.yml` before running the generator, with a warning logged to indicate which keys were removed. Users of `@techdocs/cli` should also upgrade to the latest version, which includes the fixed `@backstage/plugin-techdocs-node` dependency. Some workarounds are available. Configure TechDocs with `runIn: docker` instead of `runIn: local` to provide container isolation, though it does not fully mitigate the risk. Limit who can modify `mkdocs.yml` files in repositories that TechDocs processes; only allow trusted contributors. Implement PR review requirements for changes to `mkdocs.yml` files to detect malicious `hooks` configurations before they are merged. Use MkDocs < 1.4.0 (e.g., 1.3.1) which does not support hooks. Note: This may limit access to newer MkDocs features. Building documentation in CI/CD pipelines using `@techdocs/cli` does not mitigate this vulnerability, as the CLI uses the same vulnerable `@backstage/plugin-techdocs-node` package.6.5CVE-2026-25152backstagebackstage+2
EPSS score
0.44%
Backstage is an open framework for building developer portals, and @backstage/plugin-techdocs-node provides common node.js functionalities for TechDocs. In versions of @backstage/plugin-techdocs-node prior to 1.13.11 and 1.14.1, a path traversal vulnerability in the TechDocs local generator allows attackers to read arbitrary files from the host filesystem when Backstage is configured with `techdocs.generator.runIn: local`. When processing documentation from untrusted sources, symlinks within the docs directory are followed by MkDocs during the build process. File contents are embedded into generated HTML and exposed to users who can view the documentation. This vulnerability is fixed in` @backstage/plugin-techdocs-node` versions 1.13.11 and 1.14.1. Some workarounds are available. Switch to `runIn: docker` in `app-config.yaml` and/or restrict write access to TechDocs source repositories to trusted users only.9.8CVE-2026-29186backstagebackstage+2
EPSS score
0.95%
Backstage is an open framework for building developer portals. Prior to version 1.14.3, this is a configuration bypass vulnerability that enables arbitrary code execution. The @backstage/plugin-techdocs-node package uses an allowlist to filter dangerous MkDocs configuration keys during the documentation build process. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.2.7CVE-2026-29185backstagebackstage+2
EPSS score
0.40%
Backstage is an open framework for building developer portals. Prior to version 1.20.1, a vulnerability in the SCM URL parsing used by Backstage integrations allowed path traversal sequences in encoded form to be included in file paths. When these URLs were processed by integration functions that construct API URLs, the traversal segments could redirect requests to unintended SCM provider API endpoints using the configured server-side integration credentials. This issue has been patched in version 1.20.1.