6.4

CVE-2025-3523: mozilla thunderbird

CVSS: 6.4v3.1MediumModified
AliasesUBUNTU-CVE-2025-3523DEBIAN-CVE-2025-3523
Published 15-04-2025Last modified 13-04-2026
Open JSON

Vulnerability summary

CVE-2025-3523 is a medium (CVSS 6.4) vulnerability in mozilla thunderbird. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.4% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.32%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 16 · Related 3
DLA-4167-1DSA-5912-1OPENSUSE-SU-2025:15000-1RHSA-2025:4229RHSA-2025:4389RHSA-2025:4512

Timeline

  1. 15-04-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

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 was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.32%

Chance of exploitation in the next 30 days

Percentile

23%

Versus all other CVEs

30-day change

+0.01 pp

From 0.31% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.32%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • thunderbird< 1:128.10.0esr-1~deb12u1 | < 1:128.10.0esr-1
Mozilla1 product
Ubuntu1 product
  • thunderbird< 1:128.12.0+build1-0ubuntu0.22.04.1

3 vendors · 3 products

References

8 links