CVE-2025-66449Network attack vector

Authenticated code execution via unsanitized upload filename

Published Dec 16, 2025 · Updated Dec 16, 2025

Path traversal in C4illin ConvertX before 0.16.0 allows remote authenticated users to overwrite files and execute code via /upload. The upload handler appends the unsanitized multipart file.name value to userUploadsDir and passes the resulting path to Bun.write. Any account that can upload a file can escape the per-user directory and replace writable binaries, enabling code execution with the ConvertX process's permissions.

CVSS severity8.8
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in C4illin ConvertX before 0.16.0 allows remote authenticated users to overwrite files and execute code via /upload. The upload handler appends the unsanitized multipart file.name value to userUploadsDir and passes the resulting path to Bun.write. Any account that can upload a file can escape the per-user directory and replace writable binaries, enabling code execution with the ConvertX process's permissions.

The record

CVE
CVE-2025-66449
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
C4illin
Product
ConvertX
Classifications
CWE-73, CWE-434, CWE-22, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 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=< 0.16.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

C4illin · ConvertXversion=< 0.16.0

Published CVSS scores

8.8GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-73External Control of File Name or Path
CWE-434Unrestricted Upload of File with Dangerous Type
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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