Microsoft Edge Audio 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.
Current Exploit Price (≈)
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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.
6.9$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Edge. It has been rated as problematic. Affected by this issue is some unknown functionality of the component Audio. Performing a manipulation results in information disclosure. This vulnerability is cataloged as CVE-2021-21166. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability classified as problematic has been found in Microsoft Edge (Web Browser) (version unknown). This affects an unknown function of the component Audio. 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 shared 03/04/2021 as confirmed security guidance (Website). It is possible to read the advisory at portal.msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2021-21166. It demands that the victim is doing some kind of user interaction. Technical details are unknown but an exploit is available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 01/29/2025). The attack technique deployed by this issue is T1592 according to MITRE ATT&CK. The advisory points out:

This CVE was assigned by Chrome. Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability. Please see

It is declared as attacked. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 11/03/2021 with a due date of 11/17/2021:

Apply updates per vendor instructions.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Zero-Day.cz (608). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.2
VulDB Meta Temp Score: 6.9

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

Vendor Base Score (Microsoft): 6.8
Vendor Vector (Microsoft): 🔍

NVD Base Score: 8.8
NVD Vector: 🔍

CNA Base Score: 8.8
CNA 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: Attacked

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Zero-Day.cz: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Timelineinfo

12/21/2020 🔍
03/04/2021 +73 days 🔍
03/04/2021 +0 days 🔍
03/10/2021 +5 days 🔍
05/04/2025 +1516 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: portal.msrc.microsoft.com
Status: Confirmed

CVE: CVE-2021-21166 (🔍)
GCVE (CVE): GCVE-0-2021-21166
GCVE (VulDB): GCVE-100-170919
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 03/10/2021 10:44
Updated: 05/04/2025 05:08
Changes: 03/10/2021 10:44 (29), 03/10/2021 10:48 (26), 03/29/2021 21:56 (2), 03/29/2021 21:59 (18), 04/21/2024 08:53 (29), 06/30/2024 05:27 (2), 07/25/2024 22:17 (1), 09/11/2024 23:15 (1), 01/29/2025 19:02 (11), 05/04/2025 05:08 (3)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

Discussion

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