CVE-2019-9793: Buffer Overflow
A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations.
Note: Spectre mitigations are currently enabled for all users by default settings.
External Reference:
https://www.mozilla.org/en-US/security/advisories/mfsa2019-08/#CVE-2019-9793
Other sources
A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. Note: Spectre mitigations are currently enabled for all users by default settings.
A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. Note: Spectre mitigations are currently enabled for all users by default settings.. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Firefoxto a version that resolves this vulnerability.Fixed in 66 - Upgrade
Upgrade
Thunderbirdto a version that resolves this vulnerability.Fixed in 60.6 - Upgrade
Upgrade
Firefox ESRto a version that resolves this vulnerability.Fixed in 60.6 - Upgrade
Upgrade
debian/firefoxto a version that resolves this vulnerability.Fixed in 152.0.1-1 - Upgrade
Upgrade
debian/firefox-esrto a version that resolves this vulnerability.Fixed in 115.14.0esr-1~deb11u1Fixed in 140.12.0esr-1~deb11u1Fixed in 140.10.2esr-1~deb12u1Fixed in 140.12.0esr-1~deb12u1Fixed in 140.10.2esr-1~deb13u1Fixed in 140.12.0esr-1~deb13u1Fixed in 140.11.0esr-1Fixed in 140.12.0esr-1 - Upgrade
Upgrade
debian/thunderbirdto a version that resolves this vulnerability.Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.12.0esr-1~deb11u1Fixed in 1:140.10.1esr-1~deb12u1Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:140.10.1esr-1~deb13u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:140.11.0esr-1Fixed in 1:140.12.0esr-1 - Upgrade
Upgrade
alpine/firefox-esrto a version that resolves this vulnerability.Fixed in 60.6.1-r0 - Configuration
Keep Spectre mitigations enabled; they are enabled by default settings.
Firefox/Thunderbird Spectre mitigations = enabled
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
What is CVE-2019-9793?
CVE-2019-9793 is a vulnerability that removes some bounds checking for string, array, or typed array accesses in JavaScript if Spectre mitigations have been disabled.
What is the severity of CVE-2019-9793?
CVE-2019-9793 has a severity rating of high.
How does CVE-2019-9793 affect Firefox?
CVE-2019-9793 affects Mozilla Firefox versions up to and excluding 66.0.
How does CVE-2019-9793 affect Firefox ESR?
CVE-2019-9793 affects Mozilla Firefox ESR versions up to and excluding 60.6.
How can I fix CVE-2019-9793 in Firefox?
To fix CVE-2019-9793 in Firefox, update to version 66.0 or later.
How can I fix CVE-2019-9793 in Firefox ESR?
To fix CVE-2019-9793 in Firefox ESR, update to version 60.6 or later.