Vulnerability Details : CVE-2020-6819
Potential exploit
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.
Vulnerability category: Memory Corruption
Products affected by CVE-2020-6819
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
CVE-2020-6819 is in the CISA Known Exploited Vulnerabilities Catalog
CISA vulnerability name:
Mozilla Firefox And Thunderbird Use-After-Free Vulnerability
CISA required action:
Apply updates per vendor instructions.
CISA description:
Mozilla Firefox and Thunderbird contain a race condition vulnerability when running the nsDocShell destructor under certain conditions. The race condition creates a use-after-free vulnerability, causing unspecified impacts.
Notes:
https://nvd.nist.gov/vuln/detail/CVE-2020-6819
Added on
2021-11-03
Action due date
2022-05-03
Exploit prediction scoring system (EPSS) score for CVE-2020-6819
11.97%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 95 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2020-6819
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
6.8
|
MEDIUM | AV:N/AC:M/Au:N/C:P/I:P/A:P |
8.6
|
6.4
|
NIST | |
8.1
|
HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
2.2
|
5.9
|
NIST |
CWE ids for CVE-2020-6819
-
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.Assigned by: nvd@nist.gov (Primary)
-
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.Assigned by: nvd@nist.gov (Primary)
References for CVE-2020-6819
-
https://www.mozilla.org/security/advisories/mfsa2020-11/
Security Vulnerabilities fixed in Firefox 74.0.1 and Firefox ESR 68.6.1 — MozillaVendor Advisory
-
https://usn.ubuntu.com/4335-1/
USN-4335-1: Thunderbird vulnerabilities | Ubuntu security noticesThird Party Advisory
-
https://bugzilla.mozilla.org/show_bug.cgi?id=1620818
Access DeniedExploit;Issue Tracking
-
https://www.mozilla.org/security/advisories/mfsa2020-14/
Security Vulnerabilities fixed in Thunderbird 68.7.0 — MozillaVendor Advisory
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