CVE-2026-57963

An attacker who can send HTML chat messages (via Matrix or XMPP) can inject arbitrary styled content, phishing links, and CSS that manipulates the chat UI. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2042910	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-63/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-64/	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:thunderbird:::::esr:::*
	cpe:2.3:a:mozilla:thunderbird:::::-:::*

History

No history.

Information

Published : 2026-07-01 02:17

Updated : 2026-07-06 15:21

NVD link : CVE-2026-57963

Mitre link : CVE-2026-57963

CVE.ORG link : CVE-2026-57963

JSON object : View

Products Affected

mozilla

thunderbird

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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