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.

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)

EPSS: 0.002 (12.6th percentile) — read the EPSS interpretation.

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.

Affected products

Mozilla Thunderbird — versions 140.12.1, 152.0.1

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

security@mozilla.org (Permissions Required)
security@mozilla.org
security@mozilla.org (Vendor Advisory)
security@mozilla.org (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.