CVE-2026-16355: Vulnerability in Mozilla Firefox
CVE-2026-16355 is a critical vulnerability in Mozilla Firefox's JavaScript Engine JIT component involving miscompilation. This flaw could lead to severe impacts including confidentiality, integrity, and availability breaches. The issue was fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. No known exploits in the wild have been reported. The vulnerability has a CVSS score of 9.8, indicating critical severity.
AI Analysis
Technical Summary
CVE-2026-16355 is a JIT miscompilation vulnerability in the JavaScript Engine's JIT component of Mozilla Firefox. This vulnerability was addressed and fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. The flaw could allow an attacker to compromise confidentiality, integrity, and availability of the affected software. The Mozilla advisories confirm the fix and classify the impact as high. No active exploitation has been observed in the wild. The vulnerability is part of a broader set of security fixes released simultaneously.
Potential Impact
The vulnerability has a critical impact with a CVSS score of 9.8, affecting confidentiality, integrity, and availability (C:H/I:H/A:H). Exploitation could allow remote attackers to execute arbitrary code or cause significant disruption. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available and has been applied in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. Users and administrators should upgrade to these versions or later to mitigate this vulnerability. Since this is not a cloud service, remediation depends on applying the official patches. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-16355: Vulnerability in Mozilla Firefox
Description
CVE-2026-16355 is a critical vulnerability in Mozilla Firefox's JavaScript Engine JIT component involving miscompilation. This flaw could lead to severe impacts including confidentiality, integrity, and availability breaches. The issue was fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. No known exploits in the wild have been reported. The vulnerability has a CVSS score of 9.8, indicating critical severity.
CVSS v3.1
Score 9.8critical
Affected software
pkg:github/mozilla/firefox-esrRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-16355 is a JIT miscompilation vulnerability in the JavaScript Engine's JIT component of Mozilla Firefox. This vulnerability was addressed and fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. The flaw could allow an attacker to compromise confidentiality, integrity, and availability of the affected software. The Mozilla advisories confirm the fix and classify the impact as high. No active exploitation has been observed in the wild. The vulnerability is part of a broader set of security fixes released simultaneously.
Potential Impact
The vulnerability has a critical impact with a CVSS score of 9.8, affecting confidentiality, integrity, and availability (C:H/I:H/A:H). Exploitation could allow remote attackers to execute arbitrary code or cause significant disruption. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available and has been applied in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13. Users and administrators should upgrade to these versions or later to mitigate this vulnerability. Since this is not a cloud service, remediation depends on applying the official patches. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-07-20T21:55:59.129Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-68/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-69/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-70/","vendor":"Mozilla"}]
Threat ID: 6a5f6cb92a4a8d5989262426
Added to database: 07/21/2026, 12:57:29 UTC
Last enriched: 07/30/2026, 11:22:11 UTC
Last updated: 09/04/2026, 22:52:09 UTC
Views: 55
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