CVE-2018-18509: Medium severity Mozilla Thunderbird vulnerability

Published Feb 14, 2019
·
Updated

A flaw during verification of certain S/MIME signatures causes emails to be shown in Thunderbird as having a valid digital signature, even if the shown message contents aren't covered by the signature. The flaw allows an attacker to reuse a valid S/MIME signature to craft an email message with arbitrary content.

Affected Software

3 affected componentsFixes available
Mozilla Thunderbird<60.5.1
60.5.1
Mozilla Thunderbird<60.5.1
debian/thunderbird
1:115.12.0-1~deb11u11:140.12.0esr-1~deb11u11:140.10.1esr-1~deb12u11:140.11.0esr-1~deb12u11:140.10.1esr-1~deb13u11:140.11.0esr-1~deb13u11:140.11.0esr-11:140.12.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 60.5.1
  2. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.12.0esr-1~deb11u1Fixed in 1:140.10.1esr-1~deb12u1Fixed in 1:140.11.0esr-1~deb12u1Fixed in 1:140.10.1esr-1~deb13u1Fixed in 1:140.11.0esr-1~deb13u1Fixed in 1:140.11.0esr-1Fixed in 1:140.12.0esr-1
  3. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:115.12.0-1~deb11u1
  4. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1~deb11u1
  5. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.10.1esr-1~deb12u1
  6. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1~deb12u1
  7. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.10.1esr-1~deb13u1
  8. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1~deb13u1
  9. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.11.0esr-1
  10. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1

Event History

Feb 14, 2019
CVE Published
12:00 AM
Apr 26, 2019
CVE Published
via MITRE·04:13 PM
Data Sourced
via MITRE·04:13 PM
DescriptionWeakness
Jan 11, 2024
Data Sourced
via Launchpad·10:55 PM
Description
Dec 15, 2025
Data Sourced
via Ubuntu·06:29 PM
RemedyDescriptionSeverityAffected Software
Jun 18, 2026
Data Sourced
via Debian·03:58 AM
DescriptionAffected 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 CVE-2018-18509?

CVE-2018-18509 is a vulnerability in Thunderbird that allows an attacker to reuse a valid S/MIME signature to craft an email message with arbitrary contents.

2

How does CVE-2018-18509 impact Thunderbird?

CVE-2018-18509 causes emails to be shown in Thunderbird as having a valid digital signature, even if the shown message contents aren't covered by the signature.

3

What is the severity of CVE-2018-18509?

The severity of CVE-2018-18509 is high, with a CVSS (Common Vulnerability Scoring System) score of 5.3.

4

How can I fix CVE-2018-18509 in Thunderbird?

To fix CVE-2018-18509 in Thunderbird, you should update Thunderbird to version 60.5.1 or later.

5

Where can I find more information about CVE-2018-18509?

You can find more information about CVE-2018-18509 in the following references: [Bugzilla](https://bugzilla.mozilla.org/show_bug.cgi?id=1507218), [Mozilla Security Advisory](https://www.mozilla.org/en-US/security/advisories/mfsa2019-06/), [Full Disclosure Mailing List](http://seclists.org/fulldisclosure/2019/Apr/38)

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