Mozilla Thunderbird vulnerabilities

1,818 known vulnerabilities affecting mozilla/thunderbird.

Total CVEs

1,818

CISA KEV

actively exploited

Public exploits

Exploited in wild

Severity breakdown

CRITICAL612HIGH551MEDIUM626LOW29

Vulnerabilities

Page 1 of 91

CVE-2026-5734CRITICALCVSS 9.8fixed in 140.9.1fixed in 149.0.22026-04-07

CVE-2026-5734 [CRITICAL] CWE-787 CVE-2026-5734: Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thun 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, Thunde

nvd

CVE-2026-5735CRITICALCVSS 9.8fixed in 149.0.22026-04-07

CVE-2026-5735 [CRITICAL] CWE-787 CVE-2026-5735: Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evi 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.

nvd

CVE-2026-4701CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4701 [CRITICAL] CVE-2026-4701: Use-after-free in the JavaScript Engine component Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4691CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4691 [CRITICAL] CVE-2026-4691: Use-after-free in the CSS Parsing and Computation component Use-after-free in the CSS Parsing and Computation component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4689CRITICALCVSS 10.0fixed in 140.9.0fixed in 149.02026-03-24

CVE-2026-4689 [CRITICAL] CWE-190 CVE-2026-4689: Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This v Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

nvdosv

CVE-2026-4710CRITICALCVSS 9.8fixed in 140.9.0fixed in 149.02026-03-24

CVE-2026-4710 [CRITICAL] CWE-119 CVE-2026-4710: Incorrect boundary conditions in the Audio/Video component. This vulnerability was fixed in Firefox Incorrect boundary conditions in the Audio/Video component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

nvdosv

CVE-2026-4692CRITICALCVSS 10.0fixed in 140.9.0fixed in 149.02026-03-24

CVE-2026-4692 [CRITICAL] CVE-2026-4692: Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

nvdosv

CVE-2026-4721CRITICALCVSS 9.8fixed in 140.9.0fixed in 149.02026-03-24

CVE-2026-4721 [CRITICAL] CWE-120 CVE-2026-4721: Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. 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, Firefox ESR 115.34, Fire

nvdosv

CVE-2026-4688CRITICALCVSS 10.0≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4688 [CRITICAL] CVE-2026-4688: Sandbox escape due to use-after-free in the Disability Access APIs component Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4700CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4700 [CRITICAL] CVE-2026-4700: Mitigation bypass in the Networking: HTTP component Mitigation bypass in the Networking: HTTP component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4696CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4696 [CRITICAL] CVE-2026-4696: Use-after-free in the Layout: Text and Fonts component Use-after-free in the Layout: Text and Fonts component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4698CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4698 [CRITICAL] CVE-2026-4698: JIT miscompilation in the JavaScript Engine: JIT component JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4720CRITICALCVSS 9.8fixed in 140.9.0fixed in 149.02026-03-24

CVE-2026-4720 [CRITICAL] CWE-120 CVE-2026-4720: Memory safety bugs present in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird Memory safety bugs present in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. 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, Firefox ESR 140.9, Thunderbird 149, and Thun

nvdosv

CVE-2026-4717CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4717 [CRITICAL] CVE-2026-4717: Privilege escalation in the Netmonitor component Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4729CRITICALCVSS 9.8fixed in 149.02026-03-24

CVE-2026-4729 [CRITICAL] CWE-120 CVE-2026-4729: Memory safety bugs present in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of Memory safety bugs present in Firefox 148 and Thunderbird 148. 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 and Thunderbird 149.

nvd

CVE-2026-4716CRITICALCVSS 9.1≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4716 [CRITICAL] CVE-2026-4716: Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4702CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4702 [CRITICAL] CVE-2026-4702: JIT miscompilation in the JavaScript Engine component JIT miscompilation in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4715CRITICALCVSS 9.1≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4715 [CRITICAL] CVE-2026-4715: Uninitialized memory in the Graphics: Canvas2D component Uninitialized memory in the Graphics: Canvas2D component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

CVE-2026-4724CRITICALCVSS 9.1fixed in 149.02026-03-24

CVE-2026-4724 [CRITICAL] CWE-758 CVE-2026-4724: Undefined behavior in the Audio/Video component. This vulnerability was fixed in Firefox 149 and Thu Undefined behavior in the Audio/Video component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

nvd

CVE-2026-4705CRITICALCVSS 9.8≥ 0, < 1:140.9.0esr-1~deb11u1≥ 0, < 1:140.9.0esr-1~deb12u1+2 more2026-03-24

CVE-2026-4705 [CRITICAL] CVE-2026-4705: Undefined behavior in the WebRTC: Signaling component Undefined behavior in the WebRTC: Signaling component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

osv

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