How severe is CVE-2026-104102?

No CVSS score has been assigned to CVE-2026-104102 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-104102?

CVE-2026-104102 affects the following packages: copyparty (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-104102?

Update copyparty to 1.20.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-104102 is resolved across your whole dependency graph.

How do I detect CVE-2026-104102 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for copyparty, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-104102 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2026-104102 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-104102 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-104102?

CVE-2026-104102 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-104102?

CVE-2026-104102 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-104102 published, and has it been updated?

CVE-2026-104102 was published on October 12, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-104102 — copyparty

Fix: 9001/copyparty@b331bb1

CVE-2026-104102 is a Path Traversal vulnerability in copyparty. A fix is available for copyparty — see the affected versions and patch details below.

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

Also known asGHSA-phv8-wgjp-g4p9

Published

Oct 12, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-104102.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍copyparty

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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 the potential effect on other unrelated software which is running on the same system.

The severity is assuming the worst case (SC:H/SI:H), that the same machine is running some unrelated software that will execute new arbitrarily-named files as code, and that the copyparty process has sufficient privileges to write files into the config-folder of that unrelated software.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`copyparty`	all versions	1.20.19`pip install --upgrade 'copyparty==1.20.19'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for copyparty, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update copyparty to 1.20.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-104102 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

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

O3 Security · Impact-Aware SCA

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