Firefox vulnerabilities
667 known CVE vulnerabilities in Firefox, translated and rated.
- CVE-2026-117890Low risk· EPSS 8%
JIT miscompilation in the JavaScript Engine: JIT component of Firefox and Thunderbird. It may cause unpredictable behavior or potential security gaps. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117889Low risk· EPSS 8%
Incorrect boundary conditions in the JavaScript Engine component of Firefox and Thunderbird. It may lead to errors or potential security impacts during script execution. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117888Low risk· EPSS 8%
Uninitialized memory in the Graphics: Canvas2D component of Firefox and Thunderbird. It may lead to data leakage or unpredictable behavior. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117887Low risk· EPSS 8%
Use-after-free vulnerability in the DOM: Core & HTML component of Firefox and Thunderbird. It may lead to undefined behavior or potential code execution. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117886Low risk· EPSS 8%
Incorrect boundary conditions in the Graphics: Text component of Firefox and Thunderbird. It may lead to errors or potential security impacts during text rendering. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117885Low risk· EPSS 8%
Use-after-free vulnerability in the Layout: Grid component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117884Low risk· EPSS 8%
Use-after-free vulnerability in the Networking component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117883Low risk· EPSS 8%
Use-after-free vulnerability in the DOM: HTML Parser component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117882Low risk· EPSS 8%
Use-after-free vulnerability in the Layout component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117881Low risk· EPSS 8%
Use-after-free vulnerability in the DOM: Core & HTML component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117880Low risk· EPSS 8%
Use-after-free vulnerability in the XML component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117879Low risk· EPSS 8%
Incorrect boundary conditions vulnerability in the Layout: Tables component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117878Low risk· EPSS 8%
Use-after-free vulnerability in the Storage: IndexedDB component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117877Low risk· EPSS 8%
Use-after-free vulnerability in the Layout: Text and Fonts component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117876Low risk· EPSS 8%
Use-after-free vulnerability in the Layout: Text and Fonts component of Firefox and Thunderbird. It was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117875Low risk· EPSS 8%
Use-after-free vulnerability in the Layout: Scrolling and Overflow component of Firefox and Thunderbird. It may lead to undefined memory behavior when processing content. The vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117874Low risk· EPSS 8%
Use-after-free vulnerability in the Internationalization component of Firefox and Thunderbird. It may cause access to freed memory while processing internationalization data. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117873Low risk· EPSS 8%
Incorrect boundary conditions in the Audio/Video: Playback component of Firefox and Thunderbird. The flaw may lead to improper processing of media data. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117872Low risk· EPSS 8%
Use-after-free vulnerability in the JavaScript: Standard Library component of Firefox and Thunderbird. It may lead to access to freed memory during JavaScript execution. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117871Low risk· EPSS 8%
Invalid pointer in the Graphics component of Firefox and Thunderbird. The flaw may lead to improper memory access during graphics operations. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117870Low risk· EPSS 8%
Use-after-free vulnerability in the JavaScript Engine component of Firefox and Thunderbird. It may lead to access to freed memory during JavaScript execution. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117869Low risk· EPSS 8%
Use-after-free vulnerability in the DOM: Core & HTML component of Firefox and Thunderbird. It may lead to access to freed memory during DOM manipulation. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117868Low risk· EPSS 8%
Sandbox escape vulnerability in the DOM: Networking component of Firefox and Thunderbird. It may allow bypassing process isolation mechanisms. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117867Low risk· EPSS 8%
Use-after-free vulnerability in the Layout component of Firefox and Thunderbird. It may lead to access to freed memory during page layout processing. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117866Low risk· EPSS 8%
Privilege escalation due to use-after-free in the Graphics: Canvas2D component of Firefox and Thunderbird. It may lead to access to freed memory during Canvas2D operations. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117865Low risk· EPSS 8%
Use-after-free vulnerability in the JavaScript: GC component of Firefox and Thunderbird. It can lead to undefined memory behavior, including potential code execution. The issue was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117864Low risk· EPSS 8%
Sandbox escape vulnerability in the Form Manager component of Firefox and Thunderbird. It may allow bypassing process isolation and gaining higher privileges. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117863Low risk· EPSS 8%
Information disclosure vulnerability due to uninitialized memory in the Audio/Video component of Firefox and Thunderbird. It may lead to leakage of data from process memory. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117862Low risk· EPSS 8%
Privilege escalation vulnerability due to incorrect boundary conditions in the Networking component of Firefox and Thunderbird. It may allow gaining higher privileges within the process. Fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117861Low risk· EPSS 8%
Sandbox escape vulnerability in the DOM: Navigation component of Firefox and Thunderbird. It may allow bypassing process isolation and gaining higher privileges. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-117860Low risk· EPSS 9%
Same-origin policy bypass vulnerability in the DOM: Navigation component of Firefox and Thunderbird. It may allow access to data from other origins contrary to the security policy. Fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
- CVE-2026-109778High
A privilege escalation vulnerability in the WebExtensions component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109777Medium
Information disclosure vulnerability in the Storage: IndexedDB component. This issue was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109776Medium
Race condition vulnerability in the XPCOM component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109775Medium
Denial-of-service vulnerability in the WebRTC component. This issue was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109773Medium
Denial-of-service vulnerability in the Sync component. This issue was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109771Medium
Information disclosure vulnerability in the WebRTC: Networking component. This issue was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109770Medium
Spoofing issue in the DOM: Web Serial component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109769Medium
Information disclosure vulnerability in the Networking: Cache component. This issue was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109768Medium
Denial-of-service vulnerability in the Site Reports component. This issue was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109767Medium
Information disclosure vulnerability in the Networking component of Firefox and Thunderbird. The flaw was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109766High
Mitigation bypass in the Enterprise Policies component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109765Medium
Race condition leading to use-after-free in the Graphics: Text component of Firefox and Thunderbird. The flaw was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109764Medium
Mitigation bypass in the Enterprise Policies component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109763Medium
Mitigation bypass in the File Handling component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109762High
Incorrect boundary conditions in the SVG component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109761Medium
Use-after-free vulnerability in the JavaScript: WebAssembly component of Firefox and Thunderbird. The flaw was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109760High
Mitigation bypass in the Networking: HTTP component. Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109759High
A vulnerability in the Networking component causes a site isolation issue. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109757High
A vulnerability in the Networking component allows sandbox escape due to a race condition. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

