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CVE-2025-26696: mozilla thunderbird Authentication Bypass by Spoofing

CVSS: 7.0v3.1HighModified
AliasesUBUNTU-CVE-2025-26696DEBIAN-CVE-2025-26696
Published 10-03-2025Last modified 13-04-2026
Open JSON

Vulnerability summary

CVE-2025-26696 is a high (CVSS 7.0) Authentication Bypass by Spoofing vulnerability in mozilla thunderbird. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 27.8% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.0/10
010
High · v3.1 (CVE.org)
EPSS score
0.36%
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 13 · Related 2
DLA-4081-1DSA-5876-1RHSA-2025:2899RHSA-2025:2900RHSA-2025:2957RHSA-2025:2958

Timeline

  1. 10-03-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

Certain crafted MIME email messages that claimed to contain an encrypted OpenPGP message, which instead contained an OpenPGP signed message, were wrongly shown as being encrypted. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.36%

Chance of exploitation in the next 30 days

Percentile

28%

Versus all other CVEs

30-day change

+0.01 pp

From 0.35% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.36%

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< 1:128.8.0esr-1~deb12u1 | < 1:128.8.0esr-1
Mozilla1 product
Ubuntu1 product
  • thunderbird< 1:128.12.0+build1-0ubuntu0.22.04.1

3 vendors · 3 products

References

8 links