CyberSecBulletin

Mozilla vulnerabilities

We track 912 vulnerabilities in Mozilla products across 22 products. 911 are rated high or critical, and 15 have been exploited in real attacks. The most recent was published on November 10, 2026.

912vulnerabilities
260critical
651high
15exploited
8.7average CVSS score

Latest Mozilla vulnerabilities

  • 8.8 High severity

    Thunderbird: Improper Privilege Management

    CVE-2026-100801Mozilla

    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.

  • 9.6 Critical severity

    Firefox: Use After Free

    CVE-2026-100800Mozilla

    Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

  • 8.1 High severity

    Firefox: Missing Cryptographic Step

    CVE-2026-100798Mozilla

    Cryptography misuse in Storage: Quota Manager component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100797Mozilla

    Privilege escalation due to use-after-free in the Graphics: WebRender component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Thunderbird: Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVE-2026-100794Mozilla

    Sandbox escape due to incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 7.1 High severity

    Thunderbird: Access of Resource Using Incompatible Type

    CVE-2026-100792Mozilla

    JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100791Mozilla

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100790Mozilla

    Use-after-free in the XSLT component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100789Mozilla

    Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.8 Critical severity

    Thunderbird: Access of Uninitialized Pointer

    CVE-2026-100788Mozilla

    Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Use After Free

    CVE-2026-100786Mozilla

    Sandbox escape due to use-after-free in the Graphics component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100785Mozilla

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100784Mozilla

    Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVE-2026-100782Mozilla

    Privilege escalation due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVE-2026-100781Mozilla

    Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100780Mozilla

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100779Mozilla

    Use-after-free in the XSLT component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Use After Free

    CVE-2026-100778Mozilla

    Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100777Mozilla

    Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Thunderbird: Use After Free

    CVE-2026-100776Mozilla

    Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Protection Mechanism Failure

    CVE-2026-100775Mozilla

    Sandbox escape in the Graphics component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100774Mozilla

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100773Mozilla

    Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Thunderbird: Use After Free

    CVE-2026-100772Mozilla

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 8.1 High severity

    Firefox: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

    CVE-2026-100771Mozilla

    Undefined behavior in the DOM: Streams component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Use After Free

    CVE-2026-100770Mozilla

    Sandbox escape due to use-after-free in the DOM: Content Processes component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Thunderbird: Use After Free

    CVE-2026-100769Mozilla

    Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100767Mozilla

    Use-after-free in the Networking: Cache component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100765Mozilla

    Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

  • 8.8 High severity

    Thunderbird: Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVE-2026-100764Mozilla

    Privilege escalation due to incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

  • 9.6 Critical severity

    Firefox: Use After Free

    CVE-2026-100762Mozilla

    Sandbox escape due to use-after-free in the DOM: Content Processes component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Protection Mechanism Failure

    CVE-2026-100760Mozilla

    Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

  • 8.1 High severity

    Firefox: Use of Uninitialized Variable

    CVE-2026-100759Mozilla

    Uninitialized memory in the Storage: Quota Manager component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.6 Critical severity

    Firefox: Improper Access Control

    CVE-2026-100758Mozilla

    Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.8 High severity

    Firefox: Use After Free

    CVE-2026-100757Mozilla

    Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 8.1 High severity

    Firefox: Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVE-2026-100756Mozilla

    Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

  • 9.1 Critical severity

    Thunderbird: Out-of-bounds Read

    CVE-2026-92240Mozilla

    A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thu

  • 8.1 High severity

    Thunderbird: Out-of-bounds Read

    CVE-2026-92239Mozilla

    A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

  • 9.8 Critical severity

    Thunderbird: Inconsistent Interpretation of HTTP Requests

    CVE-2026-92238Mozilla

    A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

  • 9.1 Critical severity

    Firefox: Protection Mechanism Failure

    CVE-2026-92079Mozilla

    Mitigation bypass in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.