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Fencer Vulns
high 8.8

CVE-2020-15669 json

When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified.

published 2020-10-01 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-7656

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified. This results in a use-after-free and we presume that with enough effort it could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 68.12 and Thunderbird < 68.12.

Patch / fix

  • Mozilla Firefox ESR 68.12
  • Mozilla Thunderbird 68.12
  • firefox-esr Debian 14, Debian 13, Debian 12 68.12.0esr-1
  • thunderbird Debian 14, Debian 13, Debian 12 1:68.12.0-1

debian advisories DEBIAN-CVE-2020-15669

  • thunderbird Ubuntu 18.04 LTS 1:78.8.1+build1-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2020-15669

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 6 68.12.0-1.el6_10
  • thunderbird RHEL 8 68.12.0-1.el8_2
  • thunderbird RHEL 7 68.12.0-1.el7_8
  • firefox RHEL 6 68.12.0-1.el6_10
  • firefox RHEL 7 68.12.0-1.el7_8
  • firefox RHEL 8 78.2.0-2.el8_2
  • thunderbird RHEL 8.0 E4S 68.12.0-1.el8_0
  • thunderbird RHEL 8.1 EUS 68.12.0-1.el8_1

red hat advisories RHSA-2020:3643RHSA-2020:3634RHSA-2020:3633RHSA-2020:3632RHSA-2020:3631RHSA-2020:3558

  • MozillaThunderbird SLE Workstation Extension 15 SP2, SLE Workstation Extension 15 SP1 68.12.0-3.94.1

suse advisories SUSE-SU-2020:2552-1

  • MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
  • MozillaThunderbird openSUSE Leap 15.2 68.12.0-lp152.2.10.1
  • MozillaThunderbird openSUSE Leap 15.1 68.12.0-lp151.2.50.1

opensuse advisories openSUSE-SU-2024:10601-1openSUSE-SU-2020:1392-1openSUSE-SU-2020:1383-1

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-2020-15669 updated cvss 8.8

Mozilla: Use-After-Free when aborting an operation

  • Red Hat Enterprise Linux 5 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 78.2.0-2.el8_2, thunderbird 68.12.0-1.el8_2
    fixed: vendor fix RHSA-2020:3557
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 78.2.0-3.el8_0, thunderbird 68.12.0-1.el8_0
    fixed: vendor fix RHSA-2020:3555
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox 78.2.0-3.el8_1, thunderbird 68.12.0-1.el8_1
    fixed: vendor fix RHSA-2020:3559
  • Red Hat Enterprise Linux Client (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.12.0-1.el7_8
    fixed: vendor fix RHSA-2020:3556
  • Red Hat Enterprise Linux Desktop (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.12.0-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.12.0-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.12.0-1.el6_10
    fixed: vendor fix RHSA-2020:3558
  • Red Hat Enterprise Linux Server (v. 7) firefox 68.12.0-1.el7_8
    fixed: vendor fix RHSA-2020:3556
  • Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10
    fixed: vendor fix RHSA-2020:3558
show 5 more
  • Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8
    fixed: vendor fix RHSA-2020:3556
  • Red Hat Enterprise Linux Workstation (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10
    fixed: vendor fix RHSA-2020:3558
  • Red Hat Enterprise Linux Workstation (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8
    fixed: vendor fix RHSA-2020:3556
  • Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.12.0-1.el6_10
    fixed: vendor fix RHSA-2020:3558
  • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.12.0-1.el7_8
    fixed: vendor fix RHSA-2020:3556

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

1.12% chance of exploitation in the next 30 days, higher than 66% 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 Firefox ESR
  • Mozilla Thunderbird

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.