copyparty FTP: upload outside defined volumes (limited path traversal)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · 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 · score source

EPSS

• CVE-2026-104102: 0.31% estimated exploitation activity in the next 30 days; percentile 24.29 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

The FTP and FTPS server -- if enabled -- would allow uploading to any folder that the copyparty process had permission to write to. The FTP-server is default-disabled, and must be explicitly enabled in the config with global-option ftp or ftps to be affected. Additionally, SFTP was not affected at all; only FTP and FTPS. This was not a full read/write path-traversal; it had the following limitations: Only applied to uploads; it was not possible to read/download existing files in this manner. The output filename was not fully controllable; a randomized suffix would always be appended to the filename. Existing files could not be overwritten or appended to; only new files could be created. Filesystem-permissions would prevent writing to system folders, as copyparty surely does not run as root in most deployments. Copyparty itself will not execute arbitrary files as code by default, so this vulnerability could not be used to execute arbitrary code through copyparty. The main concern is…

Published by the source

15 Oct 2026, 20:16 UTC

Last modified by the source

15 Oct 2026, 20:30 UTC

Source last checked

26 Oct 2026, 13:55 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-phv8-wgjp-g4p9

2. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-phv8-wgjp-g4p9

4. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-phv8-wgjp-g4p9

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# Patch Next advisory brief: CVE-2026-104102

Advisory: copyparty FTP: upload outside defined volumes (limited path traversal)
IDs: CVE-2026-104102, GHSA-phv8-wgjp-g4p9
Record: https://patchnext.com/advisories/cve-2026-104102 (revision 4, source checked 26 Oct 2026, 13:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: copyparty 1.20.19. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI copyparty: affected < 1.20.19; fixed in 1.20.19

## Suggested inspection (read-only)
- `python -m pip show copyparty`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on copyparty.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-phv8-wgjp-g4p9 (GitHub-reviewed advisory GHSA-phv8-wgjp-g4p9 lists affected ranges: PyPI copyparty >=0 <1.20.19)
- Verified: https://osv.dev/vulnerability/GHSA-phv8-wgjp-g4p9 (OSV record GHSA-phv8-wgjp-g4p9 lists affected ranges: PyPI copyparty >=0 <1.20.19 (fixed))

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