CVE-2026-74989

Internally found bugs fixed in Firefox 154

Internally found bugs present in Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154 and Thunderbird 154.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-74988

Internally found bugs fixed in Firefox ESR 153.1 and Firefox 154

Internally found bugs present in Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-74990

Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154

Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-74987

Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox 154

Internally found bugs present in Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-74949

Use-after-free in the Graphics: Canvas2D component

Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-74946

Information disclosure due to incorrect boundary conditions in the Graphics: CanvasWebGL component

Information disclosure due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-118008

Privilege escalation in the DOM: Navigation component

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-100801

Privilege escalation in the DLL Services component

Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 159, Firefox ESR 153.6, Thunderbird 159, Thunderbird 153.6, Firefox 157, and Firefox ESR 140.17.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-109707

Sandbox escape due to use-after-free in the Networking component

Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

CVSS 3.1 · 9.6 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109705

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

CVSS 3.1 · 9.6 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109708

Sandbox escape due to incorrect boundary conditions in the Networking component

Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

CVSS 3.1 · 9.6 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109772

Same-origin policy bypass in the DevTools component

Same-origin policy bypass in the DevTools component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109783

Mitigation bypass in the File Handling component

Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.

CVSS 3.1 · 8.3 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109780

Mitigation bypass in the DOM: Core & HTML component

Mitigation bypass in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-109782

Mitigation bypass in the File Handling component

Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.

CVSS 3.1 · 8.3 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-109774

Invalid pointer, undefined behavior in the DOM: Notifications component

Invalid pointer, undefined behavior in the DOM: Notifications component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox

CVE-2026-8974

Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151

Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-8973

Memory safety bugs fixed in Thunderbird 151

Memory safety bugs present in Thunderbird 150. 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 151 and Thunderbird 151.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-8975

Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151

Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-16411

Memory safety bugs fixed in Thunderbird 153

Memory safety bugs present in Thunderbird 152. 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 153 and Thunderbird 153.

CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox