CVE-2026-8959— Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
Possible ATT&CK Techniques 1AI
T1210 · Exploitation of Remote ServicesAffected Version Matrix 4
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Mozilla | Firefox | 140.11≤ 140.* | unaffected |
151≤ * | unaffected | ||
| Mozilla | Thunderbird | 140.11≤ 140.* | unaffected |
151≤ * | unaffected |
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I. Basic Information for CVE-2026-8959
Vulnerability Information
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Vulnerability Title
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
Source: NVD (National Vulnerability Database)
Vulnerability Description
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Mozilla多款产品 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mozilla Firefox等都是美国Mozilla基金会的产品。Mozilla Firefox是一款开源Web浏览器。Mozilla Firefox ESR是Firefox(Web浏览器)的一个延长支持版本。Mozilla Thunderbird是一套从Mozilla Application Suite独立出来的电子邮件客户端软件。 Mozilla多款产品存在输入验证错误漏洞，该漏洞源于Widget: Win32组件存在边界条件错误，可能导致沙箱逃逸。以下产品及版本受到影响：Firefox 151之前
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Mozilla | Firefox | 140.11 ~ 140.* | - | |
| Mozilla | Thunderbird | 140.11 ~ 140.* | - |
II. Public POCs for CVE-2026-8959
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same Patch Batch · Mozilla · 2026-05-19 · 32 CVEs total
| CVE-2026-8961 | Spoofing issue in the Form Autofill component | |
| CVE-2026-8945 | Sandbox escape in Firefox and Firefox Focus for Android | |
| CVE-2026-8946 | Incorrect boundary conditions in the Audio/Video: Web Codecs component | |
| CVE-2026-8947 | Use-after-free in the DOM: Bindings (WebIDL) component | |
| CVE-2026-8948 | Same-origin policy bypass in the DOM: Networking component | |
| CVE-2026-8949 | Integer overflow in the Widget: Win32 component | |
| CVE-2026-8950 | Same-origin policy bypass in the Networking: HTTP component | |
| CVE-2026-8951 | Spoofing issue in the Toolbar component in Firefox for Android | |
| CVE-2026-8952 | Privilege escalation in the Application Update component | |
| CVE-2026-8953 | Sandbox escape due to use-after-free in the Disability Access APIs component | |
| CVE-2026-8954 | Incorrect boundary conditions, integer overflow in the Audio/Video component | |
| CVE-2026-8955 | Privilege escalation in the DOM: Workers component | |
| CVE-2026-8956 | Integer overflow in the Networking: JAR component | |
| CVE-2026-8957 | Privilege escalation in the Enterprise Policies component | |
| CVE-2026-8958 | Information disclosure, sandbox escape in the Security: Process Sandboxing component | |
| CVE-2026-8960 | Spoofing issue in WebExtensions | |
| CVE-2026-8706 | Sensitive user data could be leaked to other applications through Reader mode | |
| CVE-2026-8962 | Mitigation bypass in the DOM: Security component | |
| CVE-2026-8963 | Spoofing issue in the Web Speech component | |
| CVE-2026-8964 | Spoofing issue in the Popup Blocker component |
Showing top 20 of 32 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Firefox
- CVE-2026-8975
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbi - CVE-2026-8974
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbi - CVE-2026-8973
Memory safety bugs fixed in Thunderbird 151 - CVE-2026-8972
Privilege escalation in the WebRTC: Audio/Video component - CVE-2026-8971
Same-origin policy bypass in the Networking: JAR component
Same vendor: Mozilla
- CVE-2026-8706
Sensitive user data could be leaked to other applications th - CVE-2026-8975
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbi - CVE-2026-8974
Memory safety bugs fixed in Thunderbird 140.11 and Thunderbi - CVE-2026-8973
Memory safety bugs fixed in Thunderbird 151 - CVE-2026-8972
Privilege escalation in the WebRTC: Audio/Video component
V. Comments for CVE-2026-8959
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