VDB-157792 · CVE-2020-12409 · Bug 1629506

Mozilla Firefox up to 76.x URL Spaces authentication spoofing

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.4	$0-$5k	0.00

Summaryinfo

A vulnerability described as critical has been identified in Mozilla Firefox up to 76.x. This affects an unknown function of the component URL Handler. Executing a manipulation as part of Spaces can lead to authentication spoofing. This vulnerability is tracked as CVE-2020-12409. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 76.x (Web Browser) and classified as critical. This vulnerability affects an unknown code block of the component URL Handler. The manipulation as part of a Spaces leads to a authentication spoofing vulnerability. The CWE definition for the vulnerability is CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. As an impact it is known to affect integrity. CVE summarizes:

When using certain blank characters in a URL, they where incorrectly rendered as spaces instead of an encoded URL. This vulnerability affects Firefox < 77.

The weakness was disclosed 07/09/2020 as Bug 1629506 as not defined bug report (Bugzilla). The advisory is shared for download at bugzilla.mozilla.org. This vulnerability was named CVE-2020-12409 since 04/28/2020. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 246972 (Linux Distros Unpatched Vulnerability : CVE-2020-12409), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 77.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (246972). The entries VDB-157796, VDB-157795, VDB-157794 and VDB-157791 are pretty similar. VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Web Browser

Vendor

Mozilla

Name

Firefox

Version

76.x

License

open-source

Website

Vendor: https://www.mozilla.org/
Product: https://www.mozilla.org/en-US/firefox/

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.6
VulDB Meta Temp Score: 6.4

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

NVD Base Score: 8.8
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Authentication spoofing
CWE: CWE-290 / CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 246972
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2020-12409

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Firefox 77.0

Timelineinfo

04/28/2020 🔍
07/09/2020 +72 days 🔍
07/10/2020 +1 days 🔍
08/10/2025 +1857 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: Bug 1629506
Status: Confirmed

CVE: CVE-2020-12409 (🔍)
GCVE (CVE): GCVE-0-2020-12409
GCVE (VulDB): GCVE-100-157792
See also: 🔍

Entryinfo

Created: 07/10/2020 08:17
Updated: 08/10/2025 05:07
Changes: 07/10/2020 08:17 (45), 07/10/2020 08:22 (18), 08/10/2025 05:07 (21)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.