CVE-2020-6820
HighActively exploited (CISA KEV)
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.
SeverityHigh
CVSS8.1
Exploit probability—
Product
Mozilla Firefox and Thunderbird
PublishedApr 24, 2020
First seenApr 24, 2020
Added to KEVNov 3, 2021
Weakness typeCWE-362Race condition
How to fix
CISA required action
Apply updates per vendor instructions.
CISA due date: May 3, 2022Update
- mozilla firefox68.6.1, 74.0.1 or later
- mozilla thunderbird68.7.0 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 68.6.1, v < 74.0.1 | 68.6.1, 74.0.1 |
| mozilla thunderbird | v < 68.7.0 | 68.7.0 |
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