CVE-2020-6807: Use After Free

Published Mar 10, 2020
·
Updated

Last updated 25 August 2025

Other sources

When a device was changed while a stream was about to be destroyed, the stream-reinit task may have been executed after the stream was destroyed, causing a use-after-free and a potentially exploitable crash.

External Reference:

https://www.mozilla.org/en-US/security/advisories/mfsa2020-09/#CVE-2020-6807

— Red Hat

When a device was changed while a stream was about to be destroyed, the <code>stream-reinit</code> task may have been executed after the stream was destroyed, causing a use-after-free and a potentially exploitable crash. This vulnerability affects Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.

— Launchpad

When a device was changed while a stream was about to be destroyed, the stream-reinit task may have been executed after the stream was destroyed, causing a use-after-free and a potentially exploitable crash.

— Mozilla

Affected Software

14 affected componentsFixes available
redhat/firefox<68.6
68.6
redhat/thunderbird<68.6
68.6
Mozilla Firefox<74.0
Mozilla Firefox ESR<68.6.0
Mozilla Thunderbird<68.6.0
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=19.10
Mozilla Thunderbird<68.6
68.6
Mozilla Firefox<74
74
Mozilla Firefox ESR<68.6
68.6
debian/firefox
152.0.6-1
debian/firefox-esr
115.14.0esr-1~deb11u1140.12.0esr-1~deb11u1140.12.0esr-1~deb12u1140.12.0esr-1~deb13u1140.12.0esr-1
debian/thunderbird
1:115.12.0-1~deb11u11:140.12.0esr-1~deb11u11:140.12.0esr-1~deb12u11:140.12.0esr-1~deb13u11:140.12.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 68.6
  2. Upgrade

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

    Fixed in 68.6
  3. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 68.6
  4. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 74
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 68.6
  6. Upgrade

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

    Fixed in 152.0.6-1
  7. Upgrade

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

    Fixed in 115.14.0esr-1~deb11u1Fixed in 140.12.0esr-1~deb11u1Fixed in 140.12.0esr-1~deb12u1Fixed in 140.12.0esr-1~deb13u1Fixed in 140.12.0esr-1
  8. Upgrade

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

    Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.12.0esr-1~deb11u1Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:140.12.0esr-1
  9. Upgrade

    Upgrade Mozilla Thunderbird to a version that resolves this vulnerability.

    Fixed in 68.6

Event History

Mar 10, 2020
CVE Published
via Mozilla·12:00 AM
Mar 25, 2020
CVE Published
via MITRE·09:13 PM
Data Sourced
via MITRE·09:13 PM
DescriptionWeakness
Data Sourced
via NVD·10:15 PM
DescriptionSeverityWeaknessAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·11:51 PM
Description
Feb 23, 2026
Data Sourced
via Ubuntu·03:19 PM
RemedyDescriptionSeverityAffected Software
Jul 15, 2026
Data Sourced
via Debian·04:13 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-2020-6807?

CVE-2020-6807 is a vulnerability in Mozilla Firefox, Firefox ESR, and Thunderbird that could lead to a use-after-free and potentially exploitable crash.

2

How does CVE-2020-6807 occur?

CVE-2020-6807 occurs when a device is changed while a stream is being destroyed in Mozilla Firefox, Firefox ESR, or Thunderbird.

3

Which software versions are affected by CVE-2020-6807?

Mozilla Firefox version up to 74, Firefox ESR version up to 68.6, and Thunderbird version up to 68.6 are affected by CVE-2020-6807.

4

What is the severity of CVE-2020-6807?

CVE-2020-6807 is classified as high severity with a severity value of 7.

5

How can CVE-2020-6807 be fixed?

To fix CVE-2020-6807, users should update to the latest versions of Mozilla Firefox, Firefox ESR, or Thunderbird.

Company

Resources

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