Resource exhaustion in Mozilla Thunderbird
CVE-2026-57962
A malicious LDAP server, which a Thunderbird user is configured to query for address-book autocomplete, can stash arbitrarily large amounts of attacker-supplied data into the Thunderbird LDAP client until it crashes due to memory exhaustion. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (24.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.9% 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: 0.003 · change: +0.001
Affected products
- Mozilla Thunderbird — versions 140.12.1, 152.0.1
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2026-62/
- www.mozilla.org/security/advisories/mfsa2026-63/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-64/ (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-57962?
- CVE-2026-57962 is a medium-severity vulnerability in Mozilla Thunderbird, classified under Uncontrolled Resource Consumption. CVSS score: 5.3/10. Published 2026-07-01.
- How severe is CVE-2026-57962?
- Medium severity. CVSS v3 base score is 5.3 out of 10.