Critical severity · published Oct 6, 2026
CVE-2026-106486
Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
9.9
CVSS
0.4%
EPSS
No
On KEV
Description
Backstage is an open framework for building developer portals. Prior to 0.3.10 in @backstage/plugin-scaffolder-backend-module-bitbucket-cloud and 0.2.25 in @backstage/plugin-scaffolder-backend-module-bitbucket-server, the Bitbucket pull-request Scaffolder actions did not sufficiently validate filesystem paths. An authenticated user who can execute an eligible template and influence an allowed Bitbucket repository could affect paths outside the expected working area, potentially compromising backend confidentiality, integrity, or availability. This issue is fixed in @backstage/plugin-scaffolder-backend-module-bitbucket-cloud 0.3.10 and @backstage/plugin-scaffolder-backend-module-bitbucket-server 0.2.25.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known