VulnerabilityPublished 18 Sep 2025

CVE-2025-55912: ClipBucket · Unrestricted File Upload

Source CVE Database V5

Public exploit available (Exploit-DB) · CVSS 7.3 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

7.3High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.5% chance of exploitation in 30 days – higher than 74% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 18 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
1 Exploit-DB entry, 2 days before disclosure
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by MITRE Corporation
16 Aug 2025, 33 days before disclosure
First Exploit-DB entry (opens in a new tab)
ClipBucket 5.5.0 - Arbitrary File Upload
16 Sep 2025, 2 days before disclosure
CVE published
on cve.org
18 Sep 2025, t = 0
In Threat Radar
record ingested
18 Sep 202515:21 UTC, the same day as disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

European organizations should immediately verify if they are running ClipBucket version 5.5.0 or earlier and assess exposure of the photo_uploader.php endpoint. Specific mitigation steps include: 1) Applying vendor patches or updates as soon as they become available to address the missing access control. 2) If patches are not yet released, implement temporary access restrictions such as IP whitelisting or firewall rules to limit access to the upload endpoint only to trusted internal networks or authenticated users. 3) Conduct thorough code reviews and add authentication and authorization checks to the upload handler to ensure only authorized users can upload files. 4) Monitor web server logs for suspicious upload attempts or unusual file uploads. 5) Employ web application firewalls (WAFs) with custom rules to detect and block unauthorized upload attempts targeting the vulnerable endpoint. 6) Scan the server for any previously uploaded malicious files and remove them. 7) Educate development and operations teams about secure file upload practices to prevent similar issues in the future. 8) Regularly backup critical data and maintain incident response plans to quickly recover from potential compromises.

Description

An issue in ClipBucket 5.5.0 and prior versions allows an unauthenticated attacker can exploit the plupload endpoint in photo_uploader.php to upload arbitrary files without any authentication, due to missing access controls in the upload handler

Impact

For European organizations using ClipBucket, especially those hosting video content or media platforms, this vulnerability poses a significant risk. Successful exploitation could lead to unauthorized server access, data theft, defacement of websites, or deployment of ransomware and other malware. The ability to upload arbitrary files without authentication can compromise the confidentiality, integrity, and availability of affected systems. This could disrupt business operations, damage organizational reputation, and lead to regulatory non-compliance under GDPR due to potential data breaches. Organizations that rely on ClipBucket for customer-facing services or internal media management may face service outages or data loss. Additionally, attackers could leverage compromised servers as pivot points to infiltrate broader corporate networks, increasing the scope of impact. The threat is particularly concerning for sectors with high regulatory scrutiny or critical infrastructure dependencies, such as media companies, educational institutions, and government agencies within Europe.

CWE-434Unrestricted Upload of File with Dangerous Type (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #12OWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
Architecture and Design
Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
Architecture and Design
Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Web Service Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
File Upload (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V12.5.2 (opens in a new tab)
V13.1.5 (opens in a new tab)
V12.2.1 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

Timeline

What to do

Description

AI analysisMachine-generated, updated 18 Sep 2025, 15:21 UTC

Public exploits and detection1 Exploit-DB entry

WeaknessesCWE-434

Technical details

References

Community reviews

Related threats