CVE-2026-25728Public exploitNetwork attack vector

Authenticated RCE via pre-validation web upload

Published Feb 10, 2026 · Updated Feb 10, 2026

TOCTOU in ClipBucket V5 before 5.5.3 - #40 allows remote authenticated users to execute arbitrary PHP through avatar or background uploads. The upload_user_file() method moves the file to a predictable web-accessible path before ValidateImage() checks it, then deletes a rejected file. A low-privilege self-registered account and concurrent upload and fetch requests are required; a won race runs code as the web server user.

CVSS severity9.3
Critical
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOCTOU in ClipBucket V5 before 5.5.3 - #40 allows remote authenticated users to execute arbitrary PHP through avatar or background uploads. The upload_user_file() method moves the file to a predictable web-accessible path before ValidateImage() checks it, then deletes a rejected file. A low-privilege self-registered account and concurrent upload and fetch requests are required; a won race runs code as the web server user.

The record

CVE
CVE-2026-25728
Published
Feb 10, 2026
Updated
Feb 10, 2026
Vendor
MacWarrior
Product
ClipBucket V5
Classifications
CWE-367, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 10, 2026Record 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=< 5.5.3 - #40

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MacWarrior · ClipBucket V5version=< 5.5.3 - #40

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
9.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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.

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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 exploitPublished

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1190Exploit Public-Facing Application

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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