CVE-2025-6435
"Firefox Malicious File Extension Vulnerability"
Description
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.
INFO
Published Date :
June 24, 2025, 1:15 p.m.
Last Modified :
July 14, 2025, 7:15 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
5.9
Exploitability Score :
2.2
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-6435.
| URL | Resource |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1950056 | Permissions Required |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1961777 | Permissions Required |
| https://www.mozilla.org/security/advisories/mfsa2025-51/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2025-54/ |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-6435 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-6435 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Jul. 14, 2025
Action Type Old Value New Value Changed Description 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. 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. Added Reference https://www.mozilla.org/security/advisories/mfsa2025-54/ -
Initial Analysis by [email protected]
Jul. 03, 2025
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* versions up to (excluding) 140.0 Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=1950056 Types: Permissions Required Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=1961777 Types: Permissions Required Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2025-51/ Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 24, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-434 -
New CVE Received by [email protected]
Jun. 24, 2025
Action Type Old Value New Value Added Description 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. Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=1950056 Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=1961777 Added Reference https://www.mozilla.org/security/advisories/mfsa2025-51/
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-6435 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-6435
weaknesses.