CVE-2026-24048

low

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.

References

https://github.com/backstage/backstage/security/advisories/GHSA-q2x5-4xjx-c6p9

https://github.com/backstage/backstage/commit/27f9061d24affd1b9212fe0abd476bfc3fbaedcb

Details

Source: Mitre, NVD

Published: 2026-01-21

Risk Information

CVSS v2

Base Score: 2.1

Vector: CVSS2#AV:N/AC:H/Au:S/C:P/I:N/A:N

Severity: Low

CVSS v3

Base Score: 3.5

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N

Severity: Low