Mozilla: >> Firefox >> 149.0 Security Vulnerabilities
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
CVSS Score
7.5
EPSS Score
0.006
Published
2026-04-21
Use-after-free in the WebRTC component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
CVSS Score
7.5
EPSS Score
0.004
Published
2026-04-21
Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
CVSS Score
9.8
EPSS Score
0.004
Published
2026-04-21
Information disclosure due to uninitialized memory in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
CVSS Score
7.5
EPSS Score
0.004
Published
2026-04-21
Incorrect boundary conditions, integer overflow in the Graphics: Text component. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
CVSS Score
8.8
EPSS Score
0.004
Published
2026-04-07
Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-04-07
Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
CVSS Score
9.8
EPSS Score
0.003
Published
2026-04-07
Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
CVSS Score
9.8
EPSS Score
0.003
Published
2026-04-07
The HTTP/2 protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack.
CVSS Score
5.3
EPSS Score
0.14
Published
2016-09-06
The HTTPS protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack.
CVSS Score
5.3
EPSS Score
0.14
Published
2016-09-06