7.5

CVE-2025-3875: mozilla thunderbird Authentication Bypass by Spoofing

CVSS: 7.5v3.1HighModified
AliasesUBUNTU-CVE-2025-3875DEBIAN-CVE-2025-3875
Published 14-05-2025Last modified 13-04-2026
Open JSON

Vulnerability summary

CVE-2025-3875 is a high (CVSS 7.5) Authentication Bypass by Spoofing vulnerability in mozilla thunderbird. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 32.3% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.40%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 17 · Related 4
DLA-4167-1DSA-5921-1MGASA-2025-0168OPENSUSE-SU-2025:15131-1RHSA-2025:8196RHSA-2025:8203

Timeline

  1. 14-05-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actual address. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.40%

Chance of exploitation in the next 30 days

Percentile

32%

Versus all other CVEs

30-day change

+0.02 pp

From 0.38% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.40%

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< 1:128.10.1esr-1~deb12u1 | < 1:128.10.1esr-1
Mozilla1 product
Ubuntu1 product
  • thunderbird< 1:128.12.0+build1-0ubuntu0.22.04.1

3 vendors · 3 products

References

9 links