CVE-2020-15664
MediumCVSS 6.5Exploitation Probability (EPSS)
Elevated risk70th percentile - higher than 70% of all known CVEs
Summary
Vulnerability in Firefox browser and Thunderbird mail client. A malicious webpage could access the InstallTrigger object, potentially leading to installation of an unintended or malicious extension.
Risk Assessment
Risk of malicious extension installation in the browser or mail client, potentially leading to user data compromise.
Recommendation
Update Firefox, Thunderbird, and Firefox ESR to patched versions.
Other vulnerabilities in Firefox, Thunderbird
See all- CVE-2026-16408Critical
Integer overflow in the Audio/Video: Playback component in Firefox and Thunderbird. Fixed in versions 153.
- CVE-2026-16395Critical
Integer overflow in the Audio/Video component in Firefox and Thunderbird. Fixed in versions 153.
- CVE-2026-4729Critical
Memory safety bugs were found in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption, which could potentially allow arbitrary code execution. The vulnerabilities were fixed in Firefox 149 and Thunderbird 149.
- CVE-2026-4720Critical
Memory safety bugs were found in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code with enough effort.
- CVE-2026-2807Critical
Memory safety bugs were found in Firefox 147 and Thunderbird 147. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code. The vulnerability was fixed in Firefox 148 and Thunderbird 148.
- CVE-2026-2792Critical
Memory safety bugs were found in Firefox ESR 140.7, Firefox 147, Thunderbird ESR 140.7, and Thunderbird 147. Some of these bugs showed evidence of memory corruption and could potentially be exploited to run arbitrary code with enough effort.
- CVE-2026-74978High
Clickjacking vulnerability in the Widget component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
- CVE-2026-74977High
Integer overflow in the Graphics component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
- CVE-2026-74965High
Privilege escalation in the Shell Integration component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
- CVE-2026-74958High
Information disclosure in the WebRTC component in Firefox and Thunderbird. The issue was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
Original NVD description (English source)
By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, Firefox ESR < 78.2, and Firefox for Android < 80.