{"id":"DEBIAN-CVE-2020-6820","details":"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 \u003c 68.7.0, Firefox \u003c 74.0.1, and Firefox ESR \u003c 68.6.1.","modified":"2026-09-01T16:04:33.776093097Z","published":"2020-04-24T16:15:13.463Z","upstream":["CVE-2020-6820"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2020-6820"}],"affected":[{"package":{"name":"firefox-esr","ecosystem":"Debian:12","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"68.6.1esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}},{"package":{"name":"firefox-esr","ecosystem":"Debian:13","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"68.6.1esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}},{"package":{"name":"firefox-esr","ecosystem":"Debian:14","purl":"pkg:deb/debian/firefox-esr?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"68.6.1esr-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:12","purl":"pkg:deb/debian/thunderbird?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:68.7.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:13","purl":"pkg:deb/debian/thunderbird?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:68.7.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}},{"package":{"name":"thunderbird","ecosystem":"Debian:14","purl":"pkg:deb/debian/thunderbird?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:68.7.0-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-6820.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}