CVE-2020-15659: High severity Mozilla Firefox vulnerability

Published Jul 28, 2020
·
Updated

Last updated 25 August 2025

Other sources

Mozilla developers and community members Kevin Brosnan, Alexandru Michis, Natalia Csoregi, Jason Kratzer, Christian Holler, Simon Giesecke, Luke Wagner reported memory safety bugs present in Firefox 78. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

— Mozilla

Mozilla developers and community members Natalia Csoregi, Simon Giesecke, Jason Kratzer, Christian Holler, and Luke Wagner reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

— Mozilla

Mozilla developers and community members reported memory safety bugs present in Firefox 78 and Firefox ESR 78.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.

— Launchpad

Mozilla developers Jason Kratzer and Luke Wagner reported memory safety bugs present in Firefox 78 and Firefox ESR 68.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

Mozilla developers Jason Kratzer and Luke Wagner reported memory safety bugs present in Thunderbird 68.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

— Mozilla

Affected Software

48 affected componentsFixes available
Mozilla Firefox<79.0
Mozilla Firefox ESR<68.11
Mozilla Firefox ESR>=78.0<78.1.0
Mozilla Thunderbird<68.11
Mozilla Thunderbird>=78.0.1<78.1.0
openSUSE Leap=15.1
openSUSE Leap=15.2
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
Mozilla Thunderbird<68.11
68.11
Mozilla Thunderbird<78.1
78.1
Mozilla Firefox<79
79
Mozilla Firefox ESR<68.11
68.11
Mozilla Firefox ESR<78.1
78.1
debian/firefox
148.0.2-1
debian/firefox-esr
115.14.0esr-1~deb11u1140.8.0esr-1~deb11u1128.14.0esr-1~deb12u1140.8.0esr-1~deb12u1140.4.0esr-1~deb13u1140.8.0esr-1~deb13u1140.8.0esr-1
debian/thunderbird
1:115.12.0-1~deb11u11:140.8.0esr-1~deb11u11:140.6.0esr-1~deb12u11:140.8.0esr-1~deb12u11:140.6.0esr-1~deb13u11:140.8.0esr-1~deb13u11:140.8.0esr-1
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox<79.0-r0
79.0-r0
alpine/firefox-esr<68.11.0-r0
68.11.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/firefox-esr<78.1.0-r0
78.1.0-r0
alpine/librewolf<79.0-r0
79.0-r0
alpine/librewolf<79.0-r0
79.0-r0
alpine/librewolf<79.0-r0
79.0-r0
alpine/librewolf<79.0-r0
79.0-r0
alpine/mozjs68<68.11.0-r0
68.11.0-r0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 68.11
  2. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 78.1
  3. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 79
  4. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 68.11
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 78.1
  6. Upgrade

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

    Fixed in 148.0.2-1
  7. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 115.14.0esr-1~deb11u1Fixed in 140.8.0esr-1~deb11u1Fixed in 128.14.0esr-1~deb12u1Fixed in 140.8.0esr-1~deb12u1Fixed in 140.4.0esr-1~deb13u1Fixed in 140.8.0esr-1~deb13u1Fixed in 140.8.0esr-1
  8. Upgrade

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

    Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.8.0esr-1~deb11u1Fixed in 1:140.6.0esr-1~deb12u1Fixed in 1:140.8.0esr-1~deb12u1Fixed in 1:140.6.0esr-1~deb13u1Fixed in 1:140.8.0esr-1~deb13u1Fixed in 1:140.8.0esr-1
  9. Upgrade

    Upgrade alpine/firefox to a version that resolves this vulnerability.

    Fixed in 79.0-r0
  10. Upgrade

    Upgrade alpine/firefox-esr to a version that resolves this vulnerability.

    Fixed in 68.11.0-r0
  11. Upgrade

    Upgrade alpine/firefox-esr to a version that resolves this vulnerability.

    Fixed in 78.1.0-r0
  12. Upgrade

    Upgrade alpine/librewolf to a version that resolves this vulnerability.

    Fixed in 79.0-r0
  13. Upgrade

    Upgrade alpine/mozjs68 to a version that resolves this vulnerability.

    Fixed in 68.11.0-r0

Event History

Jul 28, 2020
CVE Published
12:00 AM
Aug 10, 2020
CVE Published
via MITRE·05:43 PM
Data Sourced
via MITRE·05:43 PM
DescriptionWeakness
Data Sourced
via NVD·06:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Data Sourced
via OSV·06:15 PM
DescriptionSeverityAffected Software
Event
06:15 PM

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is CVE-2020-15659?

CVE-2020-15659 is a vulnerability in Thunderbird, Firefox, and Firefox ESR that allows for memory corruption.

2

How can this vulnerability be exploited?

This vulnerability can be exploited by a remote attacker triggering memory corruption, potentially leading to arbitrary code execution.

3

Which versions of Thunderbird are affected?

Thunderbird versions up to 78.1 and 68.11 are affected by CVE-2020-15659.

4

Which versions of Firefox are affected?

Firefox versions up to 79 and Firefox ESR versions up to 68.11 are affected by CVE-2020-15659.

5

How can I fix CVE-2020-15659?

To fix CVE-2020-15659, it is recommended to update Thunderbird to version 78.2, Firefox to version 80, and Firefox ESR to version 68.12.

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