Backstage is an open framework for building developer portals, and @backstage/backend-defaults provides the default implementations and setup for a standard Backstage backend app. Prior to versions 0.12.2, 0.13.2, 0.14.1, and 0.15.0, the `FetchUrlReader` component, used by the catalog and other plugins to fetch content from URLs, followed HTTP redirects automatically. This allowed an attacker who controls a host listed in `backend.reading.allow` to redirect requests to internal or sensitive URLs that are not on the allowlist, bypassing the URL allowlist security control. This is a Server-Side Request Forgery (SSRF) vulnerability that could allow access to internal resources, but it does not allow attackers to include additional request headers. This vulnerability is fixed in `@backstage/backend-defaults` version 0.12.2, 0.13.2, 0.14.1, and 0.15.0. Users should upgrade to this version or later. Some workarounds are available. Restrict `backend.reading.allow` to only trusted hosts that you control and that do not issue redirects, ensure allowed hosts do not have open redirect vulnerabilities, and/or use network-level controls to block access from Backstage to sensitive internal endpoints.
Metrics
Affected Vendors & Products
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History
Fri, 23 Jan 2026 16:45:00 +0000
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Backstage
Backstage backstage |
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Backstage
Backstage backstage |
Thu, 22 Jan 2026 23:00:00 +0000
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ssvc
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Wed, 21 Jan 2026 23:00:00 +0000
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| Description | Backstage is an open framework for building developer portals, and @backstage/backend-defaults provides the default implementations and setup for a standard Backstage backend app. Prior to versions 0.12.2, 0.13.2, 0.14.1, and 0.15.0, the `FetchUrlReader` component, used by the catalog and other plugins to fetch content from URLs, followed HTTP redirects automatically. This allowed an attacker who controls a host listed in `backend.reading.allow` to redirect requests to internal or sensitive URLs that are not on the allowlist, bypassing the URL allowlist security control. This is a Server-Side Request Forgery (SSRF) vulnerability that could allow access to internal resources, but it does not allow attackers to include additional request headers. This vulnerability is fixed in `@backstage/backend-defaults` version 0.12.2, 0.13.2, 0.14.1, and 0.15.0. Users should upgrade to this version or later. Some workarounds are available. Restrict `backend.reading.allow` to only trusted hosts that you control and that do not issue redirects, ensure allowed hosts do not have open redirect vulnerabilities, and/or use network-level controls to block access from Backstage to sensitive internal endpoints. | |
| Title | Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow` | |
| Weaknesses | CWE-918 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-01-21T22:51:44.015Z
Updated: 2026-01-22T16:48:55.954Z
Reserved: 2026-01-20T22:30:11.778Z
Link: CVE-2026-24048
Updated: 2026-01-22T15:09:14.747Z
Status : Received
Published: 2026-01-21T23:15:53.580
Modified: 2026-01-21T23:15:53.580
Link: CVE-2026-24048
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