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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-57962
• https://bugzilla.mozilla.org/show_bug.cgi?id=2042872
• https://www.mozilla.org/security/advisories/mfsa2026-62
• https://www.mozilla.org/security/advisories/mfsa2026-63