CVE-2019-9793
Mozilla: Improper bounds checks when Spectre mitigations are disabled
Severity
ImportantRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · March 20, 2019
Updated · November 22, 2025
Description
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 5.9CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer