VDB-155609 · CVE-2020-6831 · Nessus 249966

Mozilla Firefox/Firefox ESR/Thunderbird WebRTC buffer overflow

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.
8.5	$25k-$100k	0.00

Summaryinfo

A vulnerability classified as critical has been found in Mozilla Firefox, Firefox ESR and Thunderbird. This vulnerability affects unknown code of the component WebRTC. The manipulation leads to buffer overflow. This vulnerability is traded as CVE-2020-6831. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Mozilla Firefox, Firefox ESR and Thunderbird (Web Browser) (version now known). It has been rated as critical. This issue affects some unknown processing of the component WebRTC. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A buffer overflow could occur when parsing and validating SCTP chunks in WebRTC. This could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.

The weakness was shared 05/26/2020. The identification of this vulnerability is CVE-2020-6831 since 01/10/2020. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $25k-$100k at the moment (estimation calculated on 08/18/2025).

The vulnerability scanner Nessus provides a plugin with the ID 249966 (Linux Distros Unpatched Vulnerability : CVE-2020-6831), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (249966). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Web Browser

Vendor

Mozilla

Name

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: 8.5
VulDB Meta Temp Score: 8.5

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

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

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

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

NVD Base Score: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
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: 249966
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2020-6831

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

01/10/2020 🔍
05/26/2020 +137 days 🔍
05/27/2020 +1 days 🔍
08/18/2025 +1908 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Status: Not defined

CVE: CVE-2020-6831 (🔍)
GCVE (CVE): GCVE-0-2020-6831
GCVE (VulDB): GCVE-100-155609

Entryinfo

Created: 05/27/2020 08:59
Updated: 08/18/2025 00:52
Changes: 05/27/2020 08:59 (35), 05/27/2020 09:04 (18), 08/18/2025 00:52 (17)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.