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Fencer Vulns
high 8.8

CVE-2020-6807 json

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 st…

published 2020-03-25 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-27953

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

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.

Patch / fix

  • Mozilla Thunderbird 68.6
  • Mozilla Firefox 74, ESR68.6
  • Mozilla Firefox ESR 68.6
  • firefox-esr Debian 14, Debian 13, Debian 12 68.6.0esr-1
  • thunderbird Debian 14, Debian 13, Debian 12 1:68.6.0-1

debian advisories DEBIAN-CVE-2020-6807

  • firefox Ubuntu 16.04 LTS 74.0+build3-0ubuntu0.16.04.1
  • firefox Ubuntu 18.04 LTS 74.0+build3-0ubuntu0.18.04.1
  • firefox Ubuntu 20.04 LTS 74.0+build3-0ubuntu1
  • thunderbird Ubuntu 16.04 LTS 1:68.7.0+build1-0ubuntu0.16.04.2
  • thunderbird Ubuntu 18.04 LTS 1:68.7.0+build1-0ubuntu0.18.04.1
  • thunderbird Ubuntu 20.04 LTS 1:68.6.0+build2-0ubuntu1

ubuntu advisories UBUNTU-CVE-2020-6807

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • thunderbird RHEL 8 68.6.0-1.el8_1
  • thunderbird RHEL 6 68.6.0-1.el6_10
  • thunderbird RHEL 7 68.6.0-1.el7_7
  • firefox RHEL 8 68.6.0-1.el8_1
  • firefox RHEL 7 68.6.0-1.el7_7
  • firefox RHEL 6 68.6.0-1.el6_10
  • thunderbird RHEL 8.0 E4S 68.6.0-1.el8_0
  • firefox RHEL 8.0 E4S 68.6.0-1.el8_0

red hat advisories RHSA-2020:0919RHSA-2020:0914RHSA-2020:0918RHSA-2020:0905RHSA-2020:0820RHSA-2020:0819

  • MozillaThunderbird SLE Workstation Extension 15 SP1 68.6.0-3.74.1
  • MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +16 more 68.6.0-109.110.1
  • MozillaFirefox SLE Module for Desktop Applications 15 SP1 68.6.0-3.75.1
  • MozillaFirefox SLES 11 SP4-LTSS 68.6.0-78.64.1

suse advisories SUSE-SU-2020:0721-1SUSE-SU-2020:0717-1SUSE-SU-2020:0686-1SUSE-SU-2020:14312-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2
  • MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
  • MozillaThunderbird openSUSE Leap 15.1 68.6.0-lp151.2.28.1
  • MozillaFirefox openSUSE Leap 15.1 68.6.0-lp151.2.33.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2024:10601-1openSUSE-SU-2020:0366-1openSUSE-SU-2020:0340-1

  • firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 74.0-r0
  • mozjs68 Alpine 3.12 68.6.0-r0
  • librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 74.0-r0
  • firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +10 more 68.6.0-r0
  • thunderbird Alpine 3.23, Alpine 3.22, Alpine 3.21 +5 more 68.6.0-r0

alpine advisories ALPINE-CVE-2020-6807

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox Arch Linux 74.0-1
  • thunderbird Arch Linux 68.6.0-1

arch linux advisories AVG-1112AVG-1115

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-6807 updated cvss 8.8

Mozilla: Use-after-free in cubeb during stream destruction

  • Red Hat Enterprise Linux 5 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 68.6.0-1.el8_1, thunderbird 68.6.0-1.el8_1
    fixed: vendor fix RHSA-2020:0820
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 68.6.0-1.el8_0, thunderbird 68.6.0-1.el8_0
    fixed: vendor fix RHSA-2020:0819
  • Red Hat Enterprise Linux Client (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.6.0-1.el7_7
    fixed: vendor fix RHSA-2020:0815
  • Red Hat Enterprise Linux Desktop (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.6.0-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.6.0-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.6.0-1.el6_10
    fixed: vendor fix RHSA-2020:0816
  • Red Hat Enterprise Linux Server (v. 7) firefox 68.6.0-1.el7_7
    fixed: vendor fix RHSA-2020:0815
  • Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10
    fixed: vendor fix RHSA-2020:0816
  • Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7
    fixed: vendor fix RHSA-2020:0815
show 4 more
  • Red Hat Enterprise Linux Workstation (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10
    fixed: vendor fix RHSA-2020:0816
  • Red Hat Enterprise Linux Workstation (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7
    fixed: vendor fix RHSA-2020:0815
  • Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.6.0-1.el6_10
    fixed: vendor fix RHSA-2020:0816
  • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.6.0-1.el7_7
    fixed: vendor fix RHSA-2020:0815

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.47% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Thunderbird
  • Mozilla Firefox
  • Mozilla Firefox ESR

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.