CVE-2025-27145Public exploit

JavaScript execution via unescaped drag-drop filenames

Published Feb 25, 2025 · Updated Feb 25, 2025

DOM-based XSS in the copyparty Web UI before 1.16.15 allows attackers to execute JavaScript through a crafted empty filename. The up2k_init function in copyparty/web/up2k.js concatenates an empty file's name into a modal message without calling esc(), so the modal parses embedded markup. A user must receive a zero-byte file and drag it into an authenticated Web UI session; script code then runs with that user's file-access privileges.

CVSS severity3.6
Low
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DOM-based XSS in the copyparty Web UI before 1.16.15 allows attackers to execute JavaScript through a crafted empty filename. The up2k_init function in copyparty/web/up2k.js concatenates an empty file's name into a modal message without calling esc(), so the modal parses embedded markup. A user must receive a zero-byte file and drag it into an authenticated Web UI session; script code then runs with that user's file-access privileges.

The record

CVE
CVE-2025-27145
Published
Feb 25, 2025
Updated
Feb 25, 2025
Vendor
copyparty
Product
copyparty
Classifications
CWE-83, CAPEC-588, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.16.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

copyparty · copypartyversion=< 1.16.15

Published CVSS scores

3.6GitHubCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-83Improper Neutralization of Script in Attributes in a Web Page
CAPEC-588DOM-Based XSS
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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