title: `@backstage/backend-common` vulnerable to path traversal through symlinks
description: `@backstage/backend-common` is a common functionality library for backends for Backstage, an open platform for building developer portals. In `@backstage/backend-common` prior to versions 0.21.1, 0.20.2, and 0.19.10, paths checks with the `resolveSafeChildPath` utility were not exhaustive enough, leading to risk of path traversal vulnerabilities if symlinks can be injected by attackers. This issue is patched in `@backstage/backend-common` versions 0.21.1, 0.20.2, and 0.19.10.
problem types: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
affected:
{
vendor: backstage
product: backstage
versions:
version: = 0.21.0, status: affected
version: < 0.19.10, status: affected
version: >= 0.20.0, < 0.20.2, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 8.7
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: HIGH
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
version: 3.1
]