CVE-2026-24048: @backstage/backend defaults Backstage Has A Possible SSRF Vulnerability
LOWCVE-2026-24048 is a LOW (CVSS 3.5) backstage has a possible ssrf vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting @backstage/backend defaults libraries in the npm ecosystem. The issue involves backstage has a possible ssrf when reading from allowed url's in `backend.reading.allow`. Remediation is available by upgrading affected packages to version 0.12.2, 0.13.2, 0.14.1.
CVE-2026-24048 at a Glance
Security Impact
CVSS: 3.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N).
How to Fix CVE-2026-24048
To remediate this vulnerability, upgrade all affected @backstage/backend defaults dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install @backstage/backend-defaults@0.12.2npm install @backstage/backend-defaults@0.13.2npm install @backstage/backend-defaults@0.14.1Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls @backstage/backend-defaultsHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-24048, inspect your project dependencies using npm:
npm ls @backstage/backend-defaultsAnalyze the terminal output to locate any version of @backstage/backend defaults in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.12.2), your application is affected.
Note: The npm ls @backstage/backend-defaults command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. In @backstage/backend defaults, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-24048 Affected @backstage/backend defaults Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
@backstage/backend-defaults
|
npm |
< 0.12.2
|
0.12.2
|
|
@backstage/backend-defaults
|
npm |
≥ 0.13.0
< 0.13.2
|
0.13.2
|
|
@backstage/backend-defaults
|
npm |
≥ 0.14.0
< 0.14.1
|
0.14.1
|
References
Frequently Asked Questions
What is CVE-2026-24048?
Which @backstage/backend defaults versions are affected?
What version fixes CVE-2026-24048?
Is @backstage/backend-defaults affected?
What is the CVSS score of CVE-2026-24048?
What CWE is associated with CVE-2026-24048?
How can I check npm dependencies for CVE-2026-24048?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-q2x5-4xjx-c6p9",
"modified" : "2026-01-22T15:41:25Z",
"published" : "2026-01-21T22:49:37Z",
"aliases" : [ "CVE-2026-24048" ],
"summary" : "Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`",
"details" : "### 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)",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "@backstage/backend-defaults"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.12.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "@backstage/backend-defaults"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0.13.0"
}, {
"fixed" : "0.13.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "@backstage/backend-defaults"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0.14.0"
}, {
"fixed" : "0.14.1"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/backstage/backstage/security/advisories/GHSA-q2x5-4xjx-c6p9"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24048"
}, {
"type" : "WEB",
"url" : "https://github.com/backstage/backstage/commit/27f9061d24affd1b9212fe0abd476bfc3fbaedcb"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/backstage/backstage"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-918" ],
"severity" : "LOW",
"github_reviewed" : true,
"github_reviewed_at" : "2026-01-21T22:49:37Z",
"nvd_published_at" : "2026-01-21T23:15:53Z"
}
}