Actively exploited · Published Apr 24, 2020 · Assigned by mozilla
CVE-2020-6819
High 8.1 Exploited
In plain English
A high-severity use-after-free in Firefox from Mozilla. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). The chance it is exploited in the next 30 days is estimated at 3.0% (higher than 88% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by May 3, 2022.
Official description
Under certain conditions, when running the nsDocShell destructor, 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | firefox | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.21 | firefox | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.22 | firefox | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.23 | firefox | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.20 | firefox-esr | 68.6.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.21 | firefox-esr | 68.6.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.22 | firefox-esr | 68.6.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.23 | firefox-esr | 68.6.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.21 | librewolf | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.22 | librewolf | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.23 | librewolf | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.24 | librewolf | 74.0.1-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.20 | thunderbird | 68.7.0-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.21 | thunderbird | 68.7.0-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.22 | thunderbird | 68.7.0-r0 | ALPINE-CVE-2020-6819 |
| Alpine:v3.23 | thunderbird | 68.7.0-r0 | ALPINE-CVE-2020-6819 |
| Debian:12 | firefox-esr | 68.6.1esr-1 | DEBIAN-CVE-2020-6819 |
| Debian:13 | firefox-esr | 68.6.1esr-1 | DEBIAN-CVE-2020-6819 |
| Debian:14 | firefox-esr | 68.6.1esr-1 | DEBIAN-CVE-2020-6819 |
| Debian:12 | thunderbird | 1:68.7.0-1 | DEBIAN-CVE-2020-6819 |
| Debian:13 | thunderbird | 1:68.7.0-1 | DEBIAN-CVE-2020-6819 |
| Debian:14 | thunderbird | 1:68.7.0-1 | DEBIAN-CVE-2020-6819 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Thunderbird | unspecified – before 68.7.0 |
| Mozilla | Firefox | unspecified – before 74.0.1 |
| Mozilla | Firefox ESR | unspecified – before 68.6.1 |
Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://www.mozilla.org/security/advisories/mfsa2020-14/ x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2020-11/ x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1620818 x_refsource_MISC
- USN-4335-1 vendor-advisory, x_refsource_UBUNTU
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-6819 government-resource