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Fencer Intel
medium 6.5

CVE-2020-6793 json

When processing an email message with an ill-formed envelope, Thunderbird could read data from a random memory location.

published 6y ago modified 4mo ago also EUVD-2020-27940

cvss
6.5
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 74%
public exploits
0
none known

Summary

When processing an email message with an ill-formed envelope, Thunderbird could read data from a random memory location. This vulnerability affects Thunderbird < 68.5.

Patch / fix

  • Mozilla Thunderbird 68.5
  • thunderbird Debian 14, Debian 13, Debian 12 1:68.5.0-1

debian advisories DEBIAN-CVE-2020-6793

  • 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

ubuntu advisories UBUNTU-CVE-2020-6793

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 7 68.5.0-1.el7_7
  • thunderbird RHEL 6 68.5.0-1.el6_10
  • thunderbird RHEL 8 68.5.0-1.el8_1
  • thunderbird RHEL 8.0 E4S 68.5.0-1.el8_0

red hat advisories RHSA-2020:0576RHSA-2020:0574RHSA-2020:0577RHSA-2020:0565

  • MozillaThunderbird SLE Workstation Extension 15 SP1 68.5.0-3.71.1

suse advisories SUSE-SU-2020:0385-1

  • MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
  • MozillaThunderbird openSUSE Leap 15.1 68.5.0-lp151.2.25.1

opensuse advisories openSUSE-SU-2024:10601-1openSUSE-SU-2020:0231-1

  • thunderbird Alpine 3.23, Alpine 3.22, Alpine 3.21 +5 more 68.5.0-r0

alpine advisories ALPINE-CVE-2020-6793

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

  • thunderbird Arch Linux 68.5.0-1

arch linux advisories AVG-1099

Is CVE-2020-6793 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2020-6793 updated cvss 6.1

Mozilla: Out-of-bounds read when processing certain email messages

  • Red Hat Enterprise Linux 5 thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) thunderbird 68.5.0-1.el8_1
    fixed: vendor fix RHSA-2020:0577
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird 68.5.0-1.el8_0
    fixed: vendor fix RHSA-2020:0565
  • Red Hat Enterprise Linux Client (v. 7) thunderbird 68.5.0-1.el7_7
    fixed: vendor fix RHSA-2020:0576
  • Red Hat Enterprise Linux Desktop (v. 6) thunderbird 68.5.0-1.el6_10 Red Hat Enterprise Linux Server Optional (v. 6) thunderbird 68.5.0-1.el6_10
    fixed: vendor fix RHSA-2020:0574
  • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird 68.5.0-1.el7_7
    fixed: vendor fix RHSA-2020:0576
  • Red Hat Enterprise Linux Workstation (v. 6) thunderbird 68.5.0-1.el6_10
    fixed: vendor fix RHSA-2020:0574
  • Red Hat Enterprise Linux Workstation (v. 7) thunderbird 68.5.0-1.el7_7
    fixed: vendor fix RHSA-2020:0576

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

1.51% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

  • Mozilla Thunderbird

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource

References

Sources

Fencer Intel 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.