Skip to content

Backstage has a Possible SSRF when reading from allowed URL's in `backend.reading.allow`

Low severity GitHub Reviewed Published Jan 21, 2026 in backstage/backstage • Updated Jan 22, 2026

Package

npm @backstage/backend-defaults (npm)

Affected versions

< 0.12.2
>= 0.13.0, < 0.13.2
>= 0.14.0, < 0.14.1

Patched versions

0.12.2
0.13.2
0.14.1

Description

Impact

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.

Patches

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.

Workarounds

  • 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
  • Use network-level controls to block access from Backstage to sensitive internal endpoints

References

References

@Rugvip Rugvip published to backstage/backstage Jan 21, 2026
Published to the GitHub Advisory Database Jan 21, 2026
Reviewed Jan 21, 2026
Published by the National Vulnerability Database Jan 21, 2026
Last updated Jan 22, 2026

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(6th percentile)

Weaknesses

Server-Side Request Forgery (SSRF)

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. Learn more on MITRE.

CVE ID

CVE-2026-24048

GHSA ID

GHSA-q2x5-4xjx-c6p9

Source code

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.