Use After Free Affecting thunderbird package, versions <1:78.4.2-1


Severity

Recommended
0.0
high
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
42.33% (99th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-ECHOLATEST-THUNDERBIRD-18319152
  • published26 Jul 2026
  • disclosed9 Dec 2020

Introduced: 9 Dec 2020

CVE-2020-26950  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Echo:latest thunderbird to version 1:78.4.2-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream thunderbird package and not the thunderbird package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.

CVSS Base Scores

version 3.1