SB2026061756 - Multiple vulnerabilities in Mozilla Thunderbird ESR

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Main Vulnerability Database SB2026061756

SB2026061756 - Multiple vulnerabilities in Mozilla Thunderbird ESR

Published: June 17, 2026

Security Bulletin ID SB2026061756
CSH Severity
High
Patch available
YES
Number of vulnerabilities 29
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 52% Medium 45% Low 3%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 29 vulnerabilities.


1) Buffer overflow (CVE-ID: CVE-2026-12308)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


2) Buffer overflow (CVE-ID: CVE-2026-12307)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


3) Buffer overflow (CVE-ID: CVE-2026-12327)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in multiple unspecified components when parsing input. A remote attacker can trigger the vulnerable behavior to execute arbitrary code.

Some of the bugs showed evidence of memory corruption.


4) Input validation error (CVE-ID: CVE-2026-12325)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in the Graphics: ImageLib component when parsing image content. A remote attacker can supply crafted image content to cause a denial of service.


5) Out-of-bounds read (CVE-ID: CVE-2026-12324)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds read in the Graphics: CanvasWebGL component when rendering WebGL content. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


6) Buffer overflow (CVE-ID: CVE-2026-12330)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to incorrect boundary conditions in the Internationalization component when parsing input. A remote attacker can supply crafted input to cause a denial of service.


7) Protection Mechanism Failure (CVE-ID: CVE-2026-12315)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass a security mitigation.

The vulnerability exists due to improper access control in the DOM: Security component when enforcing security restrictions. A remote attacker can trigger the vulnerable behavior to bypass a security mitigation.


8) Buffer overflow (CVE-ID: CVE-2026-12314)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


9) Improper access control (CVE-ID: CVE-2026-12313)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to disclose sensitive information and escape the sandbox.

The vulnerability exists due to improper access control in the Security: Process Sandboxing component when enforcing sandbox restrictions. A remote attacker can trigger the vulnerable behavior to disclose sensitive information and escape the sandbox.


10) Buffer overflow (CVE-ID: CVE-2026-12312)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


11) Improper access control (CVE-ID: CVE-2026-12311)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to disclose sensitive information and escape the sandbox.

The vulnerability exists due to improper access control in the Security: Process Sandboxing component when enforcing sandbox restrictions. A remote attacker can trigger the vulnerable behavior to disclose sensitive information and escape the sandbox.


12) Buffer overflow (CVE-ID: CVE-2026-12310)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


13) Buffer overflow (CVE-ID: CVE-2026-12309)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


14) Improper access control (CVE-ID: CVE-2026-12289)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to escalate privileges.

The vulnerability exists due to improper access control in the Graphics: WebRender component when rendering web content. A remote attacker can trigger the vulnerable component to escalate privileges.


15) Buffer overflow (CVE-ID: CVE-2026-12306)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


16) Buffer overflow (CVE-ID: CVE-2026-12305)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to cause a denial of service.


17) Improper access control (CVE-ID: CVE-2026-12304)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass the same-origin policy.

The vulnerability exists due to improper access control in the Networking: Cookies component when handling cookies. A remote attacker can trigger the vulnerable behavior to bypass the same-origin policy.


18) Protection Mechanism Failure (CVE-ID: CVE-2026-12302)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass a security mitigation.

The vulnerability exists due to improper access control in the DOM: Security component when enforcing security restrictions. A remote attacker can trigger the vulnerable component to bypass a security mitigation.


19) Buffer overflow (CVE-ID: CVE-2026-12329)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to execute arbitrary code.


20) Incorrect calculation (CVE-ID: CVE-2026-12299)

CWE-ID: CWE-682 - Incorrect Calculation

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to JIT miscompilation in the DOM: Core & HTML component when executing script. A remote attacker can supply crafted script to execute arbitrary code.


21) Buffer overflow (CVE-ID: CVE-2026-12297)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to escape the sandbox.

The vulnerability exists due to incorrect boundary conditions in the Networking component when processing network data. A remote attacker can trigger the vulnerable component to escape the sandbox.


22) Improper access control (CVE-ID: CVE-2026-12296)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to escape the sandbox.

The vulnerability exists due to improper access control in the Security: Process Sandboxing component when enforcing sandbox restrictions. A remote attacker can trigger the vulnerable behavior to escape the sandbox.


23) Buffer overflow (CVE-ID: CVE-2026-12298)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in an unspecified component when parsing input. A remote attacker can trigger the vulnerable behavior to execute arbitrary code.


24) Improper access control (CVE-ID: CVE-2026-12295)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to escape the sandbox.

The vulnerability exists due to improper access control in the DOM: Navigation component when processing navigation operations. A remote attacker can trigger the vulnerable component to escape the sandbox.


25) Improper access control (CVE-ID: CVE-2026-12294)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to escape the sandbox.

The vulnerability exists due to improper access control in the DOM: Workers component when processing worker content. A remote attacker can trigger the vulnerable component to escape the sandbox.


26) Out-of-bounds write (CVE-ID: CVE-2026-12292)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to out-of-bounds write in the Web Audio component when processing audio content. A remote attacker can trigger the vulnerable behavior to execute arbitrary code.


27) Use-after-free (CVE-ID: CVE-2026-12291)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to use-after-free in the Networking: HTTP component when handling HTTP content. A remote attacker can send crafted content to execute arbitrary code.


28) Buffer overflow (CVE-ID: CVE-2026-12290)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in Firefox ESR when processing crafted content. A remote attacker can trigger the memory safety bug to execute arbitrary code.


29) Buffer overflow (CVE-ID: CVE-2026-12328)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to memory corruption in Firefox ESR when processing crafted content. A remote attacker can trigger the memory safety bugs to execute arbitrary code.

Some of the bugs showed evidence of memory corruption.


Remediation

Install update from vendor's website.

References