Vulnerability Details CVE-2026-24048
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 11.8%
CVSS Severity
CVSS v3 Score 3.5
Products affected by CVE-2026-24048
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.10
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.11
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.12
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.13
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.3
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.4
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.5
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.7
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.8
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.1.9
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.10.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.10.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.11.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.11.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.11.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.12.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.12.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.13.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.13.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.13.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.14.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.14.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.10
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.13
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.14
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.15
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.16
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.17
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.18
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.19
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.3
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.5
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.6
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.7
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.8
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.2.9
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.3.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.3.3
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.3.4
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.4.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.4.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.5.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.5.1
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.5.3
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.6.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.7.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.8.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.8.2
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.9.0
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cpe:2.3:a:linuxfoundation:backstage/backend_defaults:0.9.1