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Fencer Intel
medium 6.8

CVE-2021-41151 json

Path Traversal in @backstage/plugin-scaffolder-backend

published 5y ago modified 4mo ago also GHSA-pvv8-8fx9-h673 , EUVD-2021-2243

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

Backstage is an open platform for building developer portals. In affected versions A malicious actor could read sensitive files from the environment where Scaffolder Tasks are run. The attack is executed by crafting a custom Scaffolder template with a `github:publish:pull-request` action and a particular source path. When the template is executed the sensitive files would be included in the published pull request. This vulnerability is mitigated by the fact that an attacker would need access to create and register templates in the Backstage catalog, and that the attack is very visible given that the exfiltration happens via a pull request. The vulnerability is patched in the `0.15.9` release of `@backstage/plugin-scaffolder-backend`.

Patch / fix

  • npm @backstage/plugin-scaffolder-backend 0.15.9
  • linuxfoundation backstage 0.15.9

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Exploit prediction

1.32% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
NVD 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:P/I:N/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm @backstage/plugin-scaffolder-backend
>=0.9.4, <0.15.9
0.15.9

Affected products

  • backstage backstage

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.