{"id":"CVE-2026-24048","aliases":["EUVD-2026-4136","GHSA-q2x5-4xjx-c6p9"],"status":"published","title":"Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`","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.","severity":{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00235,"percentile":0.14613,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-918"],"published":"2026-01-21T22:49:37Z","modified":"2026-10-28T02:30:50Z","fixes":[{"ecosystem":"npm","package":"@backstage/backend-defaults","fixed_in":["0.12.2","0.13.2","0.14.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.12.2"}]}]},{"source":"ghsa","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.13.0"},{"fixed":"0.13.2"}]}]},{"source":"ghsa","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.14.0"},{"fixed":"0.14.1"}]}]},{"source":"osv","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.12.2"}]}]},{"source":"osv","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"SEMVER","events":[{"introduced":"0.13.0"},{"fixed":"0.13.2"}]}]},{"source":"osv","ecosystem":"npm","package":"@backstage/backend-defaults","ranges":[{"type":"SEMVER","events":[{"introduced":"0.14.0"},{"fixed":"0.14.1"}]}]}],"products":[{"vendor":"backstage","product":"backstage"},{"vendor":"linuxfoundation","product":"backstage\\/backend_defaults"}],"references":[{"url":"https://github.com/backstage/backstage/security/advisories/GHSA-q2x5-4xjx-c6p9","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://github.com/backstage/backstage/commit/27f9061d24affd1b9212fe0abd476bfc3fbaedcb","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-24048","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-q2x5-4xjx-c6p9"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/24xxx/CVE-2026-24048.json","tags":["advisory"]},{"url":"https://github.com/backstage/backstage","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-24048","title":"Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`","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.","status":"published","published":"2026-01-21T22:51:44.015Z","modified":"2026-01-22T16:48:55.954Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:19:50.575061Z"}],"euvd":[{"id":"EUVD-2026-4136","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.","status":"published","published":"2026-01-21T22:51:44Z","modified":"2026-01-22T16:48:55Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T19:48:48.575559Z"}],"ghsa":[{"id":"GHSA-q2x5-4xjx-c6p9","title":"Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`","description":"### Impact\n\nThe `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.\n\nThis 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.\n\n### Patches\n\nThis 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.\n\n### Workarounds\n\n- Restrict `backend.reading.allow` to only trusted hosts that you control and that do not issue redirects\n- Ensure allowed hosts do not have open redirect vulnerabilities\n- Use network-level controls to block access from Backstage to sensitive internal endpoints\n\n### References\n\n- [OWASP SSRF Prevention Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Server_Side_Request_Forgery_Prevention_Cheat_Sheet.html)","status":"published","published":"2026-01-21T22:49:37Z","modified":"2026-01-22T15:41:25Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:39:18.564331Z"}],"nvd":[{"id":"CVE-2026-24048","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.","status":"published","published":"2026-01-21T23:15:53.58Z","modified":"2026-06-17T10:22:31.16Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:04.423757Z"}],"osv":[{"id":"CVE-2026-24048","title":"Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`","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.","status":"published","published":"2026-01-21T22:51:44.015Z","modified":"2026-10-28T02:30:50.702944837Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:44:59.079784Z"},{"id":"GHSA-q2x5-4xjx-c6p9","title":"Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`","description":"### Impact\n\nThe `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.\n\nThis 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.\n\n### Patches\n\nThis 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.\n\n### Workarounds\n\n- Restrict `backend.reading.allow` to only trusted hosts that you control and that do not issue redirects\n- Ensure allowed hosts do not have open redirect vulnerabilities\n- Use network-level controls to block access from Backstage to sensitive internal endpoints\n\n### References\n\n- [OWASP SSRF Prevention Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Server_Side_Request_Forgery_Prevention_Cheat_Sheet.html)","status":"published","published":"2026-01-21T22:49:37Z","modified":"2026-02-03T03:10:27.142022Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:46:54.055966Z"}]}}