CVE-2026-8958
HIGHCVSS 8.6/10EPSS 0.34%
Last modified
CVE-2026-8958 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.. EPSS estimates a 0.34% chance of exploitation in the next 30 days.
Description
Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.11.0 |
| Mozilla | Firefox | < 151.0.0 |
| Mozilla | Thunderbird | < 140.11 |
| Mozilla | Thunderbird | < 151.0.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2034713Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-46/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-48/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-50/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-51/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-8958?
Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
How severe is CVE-2026-8958?
CVE-2026-8958 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.
How do I fix CVE-2026-8958?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-8952Privilege escalation in the Application Update component. Th…8.8
- CVE-2026-8953Sandbox escape due to use-after-free in the Disability Acces…9.6
- CVE-2026-8954Incorrect boundary conditions, integer overflow in the Audio…7.5
- CVE-2026-8955Privilege escalation in the DOM: Workers component. This vul…8.8
- CVE-2026-8956Integer overflow in the Networking: JAR component. This vuln…9.8
- CVE-2026-8957Privilege escalation in the Enterprise Policies component. T…8.8
- CVE-2026-8959Sandbox escape due to incorrect boundary conditions in the W…9.6
- CVE-2026-8960Spoofing issue in WebExtensions. This vulnerability was fixe…7.5
- CVE-2026-8961Spoofing issue in the Form Autofill component. This vulnerab…6.5
- CVE-2026-8962Mitigation bypass in the DOM: Security component. This vulne…8.1
- CVE-2026-8963Spoofing issue in the Web Speech component. This vulnerabili…7.5
- CVE-2026-8964Spoofing issue in the Popup Blocker component. This vulnerab…7.5
Are you affected by CVE-2026-8958?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST