CVE-2025-3523

User Interface (UI) Misrepresentation of attachment URL

MEDIUM
6.4
CVSS Score
Published: April 15, 2025 at 03:06 PM UTC
Updated: June 17, 2026 at 09:20 AM UTC
1 product affected across 1 vendorThunderbird

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Severity
MEDIUM6.4
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 128.9.2129.0 ≤ v < 137.0.2
Vendor states this is fixed in 128.9.2 (unaffected)
Vendor states this is fixed in 137.0.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.4MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-451

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