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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.002 (4.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 4.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Mozilla Thunderbird — versions 128.8, 136
Public proof-of-concept exploits
References
- bugzilla.mozilla.org/show_bug.cgi (Issue Tracking)
- www.mozilla.org/security/advisories/mfsa2025-17/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-18/ (Vendor Advisory)
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.