Microsoft Edge Reader Mode 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.
5.3$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Edge and classified as problematic. This impacts an unknown function of the component Reader Mode. The manipulation results in information disclosure. This vulnerability is identified as CVE-2021-21163. The attack can be executed remotely. There is not any exploit available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability was found in Microsoft Edge (Web Browser) (the affected version is unknown). It has been classified as problematic. Affected is an unknown code of the component Reader Mode. 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 03/04/2021 as confirmed security guidance (Website). The advisory is shared for download at portal.msrc.microsoft.com. This vulnerability is traded as CVE-2021-21163. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/29/2021). The MITRE ATT&CK project declares the attack technique as T1592. 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 proof-of-concept.

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

Once again VulDB remains the best source for vulnerability data.

Productinfo

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Vendor

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License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.5

VulDB Base Score: 4.3
VulDB Temp Score: 3.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

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

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: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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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 🔍
03/29/2021 +19 days 🔍

Sourcesinfo

Vendor: microsoft.com

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

CVE: CVE-2021-21163 (🔍)
GCVE (CVE): GCVE-0-2021-21163
GCVE (VulDB): GCVE-100-170916

Entryinfo

Created: 03/10/2021 10:39
Updated: 03/29/2021 21:36
Changes: 03/10/2021 10:39 (10), 03/10/2021 10:40 (19), 03/10/2021 10:43 (26), 03/29/2021 21:32 (2), 03/29/2021 21:36 (18)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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