CVE-2020-6820
HIGH8.1⚠ KEVEPSS 3.1%Mozilla Firefox And Thunderbird Use-After-Free Vulnerability
Published: 4/24/2020Modified: 4/28/2026Added to CISA KEV: 11/3/2021
Description
Under certain conditions, when handling a ReadableStream, a race condition can cause a use-after-free. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1.
Affected packages (2)
- Debian/firefox-esrfrom 0, < 68.6.1esr-1
- Debian/thunderbirdfrom 0, < 1:68.7.0-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |