CVE-2021-23978: High severity Mozilla Thunderbird vulnerability
Mozilla developers Alexis Beingessner, Tyson Smith, Nika Layzell, and Mats Palmgren reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
Other sources
Mozilla developers Alexis Beingessner, Tyson Smith, Nika Layzell, and Mats Palmgren reported memory safety bugs present in Thunderbird 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
— Mozilla
Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/firefoxto a version that resolves this vulnerability.Fixed in 118.0.2-1 - Upgrade
Upgrade
debian/firefox-esrto a version that resolves this vulnerability.Fixed in 91.12.0esr-1~deb10u1Fixed in 115.3.1esr-1~deb10u1Fixed in 102.15.0esr-1~deb11u1Fixed in 115.3.1esr-1~deb11u1Fixed in 102.15.1esr-1~deb12u1Fixed in 115.3.0esr-1~deb12u1Fixed in 115.3.0esr-1 - Upgrade
Upgrade
debian/thunderbirdto a version that resolves this vulnerability.Fixed in 1:91.12.0-1~deb10u1Fixed in 1:115.3.1-1~deb10u1Fixed in 1:102.13.1-1~deb11u1Fixed in 1:115.3.1-1~deb11u1Fixed in 1:102.15.1-1~deb12u1Fixed in 1:115.3.1-1~deb12u1Fixed in 1:115.3.1-1 - Upgrade
Upgrade
Thunderbirdto a version that resolves this vulnerability.Fixed in 78.8 - Upgrade
Upgrade
Firefoxto a version that resolves this vulnerability.Fixed in 86 - Upgrade
Upgrade
Firefox ESRto a version that resolves this vulnerability.Fixed in 78.8 - Upgrade
Upgrade
alpine/firefoxto a version that resolves this vulnerability.Fixed in 87.0-r0 - Upgrade
Upgrade
alpine/firefox-esrto a version that resolves this vulnerability.Fixed in 78.8.0-r0 - Upgrade
Upgrade
alpine/librewolfto a version that resolves this vulnerability.Fixed in 87.0-r0 - Upgrade
Upgrade
alpine/mozjs78to a version that resolves this vulnerability.Fixed in 78.8.0-r0 - Upgrade
Upgrade
alpine/thunderbirdto a version that resolves this vulnerability.Fixed in 78.9.0-r0
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
What is the severity of CVE-2021-23978?
CVE-2021-23978 has been classified with a moderate severity level due to potential memory corruption issues.
How do I fix CVE-2021-23978?
To fix CVE-2021-23978, update Firefox to version 86.0 or later, or Firefox ESR to version 78.8 or later.
What versions of Firefox are affected by CVE-2021-23978?
CVE-2021-23978 affects Firefox versions prior to 86.0 and Firefox ESR versions prior to 78.8.
Is Thunderbird affected by CVE-2021-23978?
Yes, Thunderbird versions prior to 78.8 are also affected by CVE-2021-23978.
What should I do if I cannot update to a secure version for CVE-2021-23978?
If unable to update, consider using an alternative browser until a secure version can be installed.