Mozilla Firefox up to 139 File Extension unrestricted upload

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.1$5k-$25k0.00

Summaryinfo

A vulnerability categorized as problematic has been discovered in Mozilla Firefox up to 139. This impacts an unknown function of the component File Extension Handler. Executing a manipulation can lead to an unknown weakness. This vulnerability is tracked as CVE-2025-6435. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 139 and classified as problematic. This vulnerability affects an unknown functionality of the component File Extension Handler. The CWE definition for the vulnerability is CWE-434. The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment. As an impact it is known to affect integrity. CVE summarizes:

If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious executable. This vulnerability affects Firefox < 140 and Thunderbird < 140.

The advisory is available at bugzilla.mozilla.org. This vulnerability was named CVE-2025-6435 since 06/20/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 11/14/2025). This vulnerability is assigned to T1608.002 by the MITRE ATT&CK project.

The vulnerability scanner Nessus provides a plugin with the ID 242306 (SUSE SLES12 Security Update : MozillaFirefox, MozillaFirefox-branding-SLE (SUSE-SU-2025:02339-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 140 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (242306), EUVD (EUVD-2025-19016) and CERT Bund (WID-SEC-2025-1850). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Xerox FreeFlow Print Server

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Unrestricted upload
CWE: CWE-434 / CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 242306
Nessus Name: SUSE SLES12 Security Update : MozillaFirefox, MozillaFirefox-branding-SLE (SUSE-SU-2025:02339-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Firefox 140

Timelineinfo

06/20/2025 🔍
06/24/2025 +4 days 🔍
06/24/2025 +0 days 🔍
11/14/2025 +142 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2025-6435 (🔍)
GCVE (CVE): GCVE-0-2025-6435
GCVE (VulDB): GCVE-100-313762
EUVD: 🔍
CERT Bund: WID-SEC-2025-1850 - Xerox FreeFlow Print Server: Mehrere Schwachstellen erm&ouml;glichen nicht spezifizierten Angriff

Entryinfo

Created: 06/24/2025 15:34
Updated: 11/14/2025 00:07
Changes: 06/24/2025 15:34 (54), 06/24/2025 22:41 (1), 07/03/2025 18:25 (3), 07/18/2025 22:11 (2), 08/17/2025 01:41 (7), 11/14/2025 00:07 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

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