CVE-2026-118175

Content of other messages could be included when replying to a crafted message

Published Oct 27, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into the message being composed, without showing a blocked content warning. If the user sent the message, the content of the other message was disclosed to the recipients. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4877-1 thunderbird security update
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Type Values Removed Values Added
Weaknesses CWE-201
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-200
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla thunderbird
Vendors & Products Mozilla
Mozilla thunderbird
Type Values Removed Values Added
Description When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into the message being composed, without showing a blocked content warning. If the user sent the message, the content of the other message was disclosed to the recipients. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Title Content of other messages could be included when replying to a crafted message
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Nov 4, 2026, 4:49 PM
Reserved
Oct 27, 2026, 6:16 PM
Status
Deferred
Published
Oct 27, 2026, 7:17 PM
Modified
Nov 4, 2026, 5:17 PM
Severity
Moderate
Public date
Oct 27, 2026, 6:16 PM