CVE-2020-1242 — Microsoft Edge Information Disclosure Vulnerability

Executive Summary

An information disclosure vulnerability exists in the way that Microsoft Edge handles cross-origin requests. An attacker who successfully exploited this vulnerability could determine the origin of all webpages in the affected browser. In a web-based attack scenario, an attacker could host a website that is used to attempt to exploit the vulnerability. Additionally, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could be used to exploit the vulnerability. However, in all cases an attacker would have no way to force users to view attacker-controlled content. Instead, an attacker would have to convince users to take action. For example, an attacker could trick users into clicking a link that takes them to the attacker's site. The security update addresses the vulnerability by correcting how Microsoft Edge handles cross-origin requests.

Overview

5.3

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Released Jun 9 2020

Last Updated Jun 9 2020

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.0377 — 0.88527 percentile

NVD CVSS 5.3 MEDIUM — differs from MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

Low

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 3.9

EPSS Score

0.0377

probability of exploitation in the next 30 days

0.88527 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

16 affected products

Product	KB Article	Severity	Impact	Restart Required
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for 32-bit Systems	`4561621 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for ARM64-based Systems	`4561621 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1803 for x64-based Systems	`4561621 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1809 for 32-bit Systems	`4561608 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1809 for ARM64-based Systems	`4561608 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1809 for x64-based Systems	`4561608 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1903 for 32-bit Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1903 for ARM64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1903 for x64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1909 for 32-bit Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1909 for ARM64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 1909 for x64-based Systems	`4560960 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 2004 for 32-bit Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 2004 for ARM64-based Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows 10 Version 2004 for x64-based Systems	`4557957 (Security Update)`	Important	Information Disclosure	Yes
Microsoft Edge (EdgeHTML-based) on Windows Server 2019	`4561608 (Security Update)`	Low	Information Disclosure	Yes

Patches

4 patches

Article	Type	Restart
`4561621`	Security Update	Yes
`4561608`	Security Update	Yes
`4560960`	Security Update	Yes
`4557957`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

@Windowsrcer

References

MSRC Advisory MITRE NVD