PsiTransfer is an open source, self-hosted file sharing solution. Prior to version 2.4.3, the upload PATCH flow under /files/:uploadId validates the mounted request path using the still-encoded req.path, but the downstream tus handler later writes using the decoded req.params.uploadId. In deployments that use a supported custom PSITRANSFER_UPLOAD_DIR whose basename prefixes a startup-loaded JavaScript path, such as conf, an unauthenticated attacker can create config.<NODE_ENV>.js in the application root. The attacker-controlled file is then executed on the next process restart. Version 2.4.3 contains a patch.
Exploitability
AV:NAC:HPR:NUI:RScope
S:UImpact
C:HI:HA:H7.5/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HInput Validation