CVE-2026-104102

5.3Medium

Published 12 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash

5.3Medium

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None
Impact: Limited impact
Weakness: CWE-22

Impact

Authenticated low-privileged users can write arbitrary files outside designated volumes anywhere the server process has write permissions. This requires network access, an account, and FTP or FTPS to be explicitly enabled.

Root cause

Improper path validation in FTP upload handling allows path traversal sequences to escape configured volumes.

Affected systems

copyparty prior to 1.20.19

CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Fix & remediation

Upgrade copyparty to version 1.20.19 or later. If patching immediately is not possible, disable FTP and FTPS in the server configuration.

shell

$ pip install --upgrade copyparty==1.20.19

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD description

copyparty is a portable file server. Prior to 1.20.19, FTP upload path handling does not confine destinations to configured copyparty volumes. When FTP or FTPS is explicitly enabled, a low-privileged authenticated user can submit traversal paths during upload to create a new file outside configured volumes wherever the copyparty process has write permission. The attacker cannot read or overwrite files, the output name receives a randomized suffix, and copyparty does not execute the file; however, unrelated software on the same host could process the newly created file. This issue is fixed in version 1.20.19.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-104102