Mozilla Firefox up to 84.x Screen Sharing information disclosure

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.
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mozilla Firefox up to 84.x. The affected element is an unknown function of the component Screen Sharing Handler. Performing a manipulation results in information disclosure. This vulnerability is identified as CVE-2021-23958. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Mozilla Firefox up to 84.x (Web Browser). This affects an unknown functionality of the component Screen Sharing Handler. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality.

The weakness was released 02/26/2021. It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is uniquely identified as CVE-2021-23958. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 247360 (Linux Distros Unpatched Vulnerability : CVE-2021-23958), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 85.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (247360). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

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

NVD Base Score: 6.5
NVD Vector: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / 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: 247360
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2021-23958

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Firefox 85.0

Timelineinfo

01/13/2021 🔍
02/26/2021 +44 days 🔍
02/26/2021 +0 days 🔍
08/11/2025 +1626 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-23958 (🔍)
GCVE (CVE): GCVE-0-2021-23958
GCVE (VulDB): GCVE-100-170451

Entryinfo

Created: 02/26/2021 09:45
Updated: 08/11/2025 01:26
Changes: 02/26/2021 09:45 (41), 03/05/2021 13:22 (5), 03/05/2021 13:25 (18), 08/11/2025 01:26 (17)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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