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-2026-113868

Uninitialized memory disclosure and out-of-bounds read in POP3 and SMTP NTLM authentication

When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Thunderbird

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

CVE-2026-8093

Memory safety bugs fixed in Thunderbird 150.0.2

Memory safety bugs present in Thunderbird 150.0.1. 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 150.0.2 and Thunderbird 150.0.2.

CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12317

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12314

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12312

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12310

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12309

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12308

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12307

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird

CVE-2026-12306

Memory safety bug fixed in Thunderbird 152

Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Mozilla

Products

Firefox Thunderbird