Vulnerability in Mozilla Thunderbird

CVE-2025-26695

When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

EPSS: 0.001 (4.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.

Affected products

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-26695?
CVE-2025-26695 is a medium-severity vulnerability in Mozilla Thunderbird. CVSS score: 5.3/10. Published 2025-03-10.
How severe is CVE-2025-26695?
Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2025-26695 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.