CVE-2026-57962: Denial-of-service via malicious LDAP address-book server

Published Jun 30, 2026
·
Updated

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.

Affected Software

5 affected componentsFixes available
Mozilla Thunderbird>=<=152.0.1, >=<=140.12.1
Mozilla Thunderbird<140.12.1
140.12.1
Mozilla Thunderbird<152.0.1
152.0.1
Mozilla Thunderbird<140.12.1
Mozilla Thunderbird<152.0.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 140.12.1
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 152.0.1
  3. Upgrade

    Upgrade thunderbird to a version that resolves this vulnerability.

    Fixed in 152.0.1
  4. Upgrade

    Upgrade thunderbird to a version that resolves this vulnerability.

    Fixed in 140.12.1

Event History

Jun 30, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
Jul 1, 2026
CVE Published
via MITRE·12:58 AM
Data Sourced
via MITRE·12:58 AM
Description
Data Sourced
via NVD·02:17 AM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-57962?

The severity of CVE-2026-57962 is medium with a CVSS score of 5.3.

2

How do I fix CVE-2026-57962?

To fix CVE-2026-57962, users should update Mozilla Thunderbird to the latest version that addresses this vulnerability.

3

What kind of attack does CVE-2026-57962 enable?

CVE-2026-57962 enables a denial-of-service attack via a malicious LDAP address-book server.

4

What are the potential impacts of CVE-2026-57962?

The potential impacts of CVE-2026-57962 include crashing the Thunderbird client due to memory exhaustion.

5

Who is affected by CVE-2026-57962?

Users of Mozilla Thunderbird who interact with malicious LDAP servers are affected by CVE-2026-57962.

Company

Resources

Contact

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