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CVE-2020-6820

8.1 · HIGHActively Exploited

Under certain conditions, when handling a ReadableStream, a race condition can cause a use-after-free.

Published Apr 24, 2020CWE-362EPSS 7.06%

Overview

CVE-2020-6820 is a high-severity vulnerability. It was published on April 24, 2020 and has a CVSS 3.1 base score of 8.1 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refbugzilla.mozilla.org/show_bug.cgi?id=1626728Refusn.ubuntu.com/4335-1/Refwww.mozilla.org/security/advisories/mfsa2020-11/Refwww.mozilla.org/security/advisories/mfsa2020-14/Refbugzilla.mozilla.org/show_bug.cgi?id=1626728Refusn.ubuntu.com/4335-1/Refwww.mozilla.org/security/advisories/mfsa2020-11/Refwww.mozilla.org/security/advisories/mfsa2020-14/CISAwww.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-6820

How CyberStrike helps

Frequently asked questions

What is CVE-2020-6820?

CVE-2020-6820 is a high-severity vulnerability. It was published on April 24, 2020 and has a CVSS 3.1 base score of 8.1 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2020-6820?

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2020-6820?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2020-6820?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2020-6820 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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