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GHSA-q2x5-4xjx-c6p9

LowCVSS 3.5 / 10
Published Jan 21, 2026·Last modified Feb 3, 2026
Affected Components(0)

No affected components available

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

Risk Scores
Base Score
3.5

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information.

Threat Intelligence
3.2

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
0.20%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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Low severity
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