CVE-2025-3932

thunderbird: Tracking Links in Attachments Bypassed Remote Content Blocking

Severity Score

6.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.

The Mozilla Foundation's Security Advisory describes the following issue: It is possible to craft an email that shows a tracking link as an attachment. If the user attempts to open the attachment, Thunderbird automatically accesses the link. The configuration to block remote content does not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email.

Multiple security issues were discovered in Thunderbird, which could result in spoofing of From: mail headers, execution of JavaScript or information disclosure. For the stable distribution (bookworm), these problems have been fixed in version 1:128.10.1esr-1~deb12u1.

*Credits: Dario Weißer

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Complete

Integrity

None

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2025-04-25 CVE Reserved
2025-05-14 CVE Published
2025-05-15 CVE Updated
2025-07-08 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-288: Authentication Bypass Using an Alternate Path or Channel

CAPEC

References (5)

URL	Tag	Source
https://bugzilla.mozilla.org/show_bug.cgi?id=1960412
https://www.mozilla.org/security/advisories/mfsa2025-34
https://www.mozilla.org/security/advisories/mfsa2025-35

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2025-3932	2025-06-10
https://bugzilla.redhat.com/show_bug.cgi?id=2366297	2025-06-10

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				*		-		Affected
Oracle Search vendor "Oracle"		Linux Search vendor "Oracle" for product "Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Aus Search vendor "Redhat" for product "Rhel Aus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel E4s Search vendor "Redhat" for product "Rhel E4s"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Eus Search vendor "Redhat" for product "Rhel Eus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Tus Search vendor "Redhat" for product "Rhel Tus"				*		-		Affected
Amazon Search vendor "Amazon"		Linux Search vendor "Amazon" for product "Linux"				*		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				*		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				*		-		Affected
Opensuse Search vendor "Opensuse"		Leap Search vendor "Opensuse" for product "Leap"				*		-		Affected
Oracle Search vendor "Oracle"		Linux Search vendor "Oracle" for product "Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Aus Search vendor "Redhat" for product "Rhel Aus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel E4s Search vendor "Redhat" for product "Rhel E4s"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Eus Search vendor "Redhat" for product "Rhel Eus"				*		-		Affected
Redhat Search vendor "Redhat"		Rhel Tus Search vendor "Redhat" for product "Rhel Tus"				*		-		Affected
Slackware Search vendor "Slackware"		Slackware Linux Search vendor "Slackware" for product "Slackware Linux"				*		-		Affected
Suse Search vendor "Suse"		Packagehub Search vendor "Suse" for product "Packagehub"				*		-		Affected
Suse Search vendor "Suse"		Sle-we Search vendor "Suse" for product "Sle-we"				*		-		Affected
Suse Search vendor "Suse"		Sled Search vendor "Suse" for product "Sled"				*		-		Affected
Suse Search vendor "Suse"		Sles Search vendor "Suse" for product "Sles"				*		-		Affected
Suse Search vendor "Suse"		Sles Sap Search vendor "Suse" for product "Sles Sap"				*		-		Affected