macOS · Application version · August 12, 2026

Mozilla Firefox 154.0

Mozilla Firefox 154.0, released August 12, 2026, fixes 16 CVEs in Mozilla Firefox. None of them is reported as exploited. Patch Radar priority: Urgent. The latest Mozilla Firefox is 159.0.1, which also fixes every one of these CVEs.

Urgent

Superseded. The latest Mozilla Firefox is 159.0.1, which also fixes every CVE on this page. Install that instead.

CVEs closed

5 rated Critical

Exploited

None reported

Highest CVSS

10.0

Base score, 0 to 10

Highest EPSS

0.0057

47th percentile

Priority of the 16 CVEs

Patch now 0
                                Urgent 5
                                High 10
                                Routine 1

Applies to

Product	Version
Mozilla Firefox	154.0

CVEs this fix closes

Priority	CVE	Title	CVSS	EPSS	Exploitation
Urgent	CVE-2026-74989	Internally found bugs fixed in Thunderbird 154	9.8	0.0057	None reported
Urgent	CVE-2026-74956	Same-origin policy bypass in the DOM: Service Workers component	9.1	0.0050	None reported
Urgent	CVE-2026-75874	Sandbox escape in the Remote Settings Client component	10.0	0.0046	None reported
Urgent	CVE-2026-74940	Use-after-free in the Graphics: Text component	9.8	0.0041	None reported
Urgent	CVE-2026-74979	Mitigation bypass in the Add-ons Manager component	9.8	0.0031	None reported
High	CVE-2026-74958	Information disclosure in the WebRTC component	7.5	0.0045	None reported
High	CVE-2026-74947	Privilege escalation due to invalid pointer in the Graphics component	8.8	0.0045	None reported
High	CVE-2026-74938	Mitigation bypass in the JavaScript: GC component	9.1	0.0044	None reported
High	CVE-2026-74954	Information disclosure due to side-channel in the Storage: Cache API component	7.5	0.0044	None reported
High	CVE-2026-74937	Use-after-free in the JavaScript: GC component	8.8	0.0044	None reported
High	CVE-2026-74950	Privilege escalation in the Downloads API component	8.8	0.0042	None reported
High	CVE-2026-74952	Privilege escalation in the Application Update component	8.8	0.0042	None reported
High	CVE-2026-74955	Privilege escalation in the Request Handling component	8.8	0.0042	None reported
High	CVE-2026-74965	Privilege escalation in the Shell Integration component	8.8	0.0030	None reported
High	CVE-2026-74963	Same-origin policy bypass in the Networking: Cookies component	7.5	0.0012	None reported
Routine	CVE-2026-74968	Site isolation issue in the Graphics: WebRender component	5.4	0.0016	None reported

Other Mozilla Firefox versions with security fixes

Mozilla Firefox 153.5.0
Mozilla Firefox
Mozilla Firefox 157.0.1
Mozilla Firefox
Mozilla Firefox 157.0
Mozilla Firefox
Mozilla Firefox 156.0
Mozilla Firefox
Mozilla Firefox 140.16.0
Mozilla Firefox
Mozilla Firefox 155.0
Mozilla Firefox

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