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TI-2025-20002 Aliases CVE-2025-27145GHSA-m2jw-cj8v-937r

copyparty renders unsanitized filenames as HTML when user uploads empty files

Priority MEDIUM 60CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

copyparty, a portable file server, has a DOM-based cross-site scripting vulnerability in versions prior to 1.16.15. The vulnerability is considered low-risk. By handing someone a maliciously-named file, and then tricking them into dragging the file into copyparty's Web-UI, an attacker could execute arbitrary javascript with the same privileges as that user. For example, this could give unintended read-access to files owned by that user. The bug is triggered by the drag-drop action itself; it is not necessary to actually initiate the upload. The file must be empty (zero bytes). Note that, as a general-purpose webserver, it is intentionally possible to upload HTML-files with arbitrary javascript in `<script>` tags, which will execute when the file is opened. The difference is that this vulnerability would trigger execution of javascript during the act of uploading, and not when the uploaded file was opened. Version 1.16.15 contains a fix.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00469 40th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed copyparty (9001): 1.16.15copyparty (PyPI): 1.16.15

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
9001copypartybefore 1.16.151.16.15Patch availableCNA
—copyparty (PyPI)before 1.16.151.16.15Patch availableGHSA-m2jw-cj8v-937r
  • copyparty Vendor9001 Affected before 1.16.15 Fixed in 1.16.15 Patch available CNA
  • copyparty (PyPI) Vendor— Affected before 1.16.15 Fixed in 1.16.15 Patch available GHSA-m2jw-cj8v-937r

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:9001:copyparty:*:*:*:*:*:*:*:*before 1.16.15Vulnerable9001
  • cpe:2.3:a:9001:copyparty:*:*:*:*:*:*:*:* Versions before 1.16.15 Vulnerable ·9001

Remediation

  • Fix · CNA copyparty (9001) Fixed in 1.16.15
  • Fix · GHSA-m2jw-cj8v-937r copyparty (PyPI) Fixed in 1.16.15 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-27145
  2. 2026-10-03 Alias added: GHSA-m2jw-cj8v-937r

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • TI-2025-34551 Copyparty is vulnerable to Regex Denial of Service (ReDoS) attacks through "Recent Uploads" page CVSS 3.1HIGH 7.5
  • TI-2023-19082 Path traversal in copyparty CVSS 3.1HIGH 7.5
  • TI-2023-21990 Cross Site Scripting vulnerability in copyparty before 1.9.2 allows a local attacker to… CVSS 3.1HIGH 7.8
  • TI-2023-19881 copyparty vulnerable to reflected cross-site scripting via k304 parameter CVSS 3.1MEDIUM 6.3
  • TI-2025-34228 copyparty has a DOM-Based XSS vulnerability when displaying multimedia metadata CVSS 3.1MEDIUM 6.1
  • TI-2025-34360 copyparty Reflected XSS via Filter Parameter CVSS 3.1MEDIUM 6.3
See all 11 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences