CVSS 3.1
8.1 highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HCVE-2020-6820
High (8.1) in Mozilla Firefox and Thunderbird. In CISA KEV since 2021-11-03. EPSS 7.1% chance of exploitation in the next 30 days.
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.
Severity
- EPSS
- 7.1% chance of exploitation in the next 30 days; higher than 94% of CVEs (scores of 2026-10-31)
- CISA KEV
- listed 2021-11-03, due 2022-05-03
- CWE
- CWE-362
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mozilla:firefox
- mozilla:thunderbird