cbcvebase.
CVE-2026-3889
published 2026-03-24

CVE-2026-3889: Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

PriorityP429medium6.5CVSS 3.1
AVNACLPRNUIRSUCNIHAN
EPSS
0.20%
10.4th percentile
Spoofing issue in Thunderbird. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

Affected

8 ranges
VendorProductVersion rangeFixed in
debianthunderbird< thunderbird 1:140.9.0esr-1~deb12u1 (bookworm)thunderbird 1:140.9.0esr-1~deb12u1 (bookworm)
mozillafirefox
mozillathunderbird< 140.9.0140.9.0
mozillathunderbird< 149.0149.0
mozillathunderbird>= 0 < 1:140.9.0esr-1~deb11u11:140.9.0esr-1~deb11u1
mozillathunderbird>= 0 < 1:140.9.0esr-1~deb12u11:140.9.0esr-1~deb12u1
mozillathunderbird>= 0 < 1:140.9.0esr-1~deb13u11:140.9.0esr-1~deb13u1
mozillathunderbird>= 0 < 1:140.9.0esr-11:140.9.0esr-1

CVSS provenance

nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
osv6.5MEDIUM
vendor_debian6.5MEDIUM
vendor_redhat6.5MEDIUM
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.