SB2026051267 - Multiple vulnerabilities in Mozilla Firefox

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Main Vulnerability Database SB2026051267

SB2026051267 - Multiple vulnerabilities in Mozilla Firefox

Published: May 12, 2026 Updated: May 18, 2026

Security Bulletin ID SB2026051267
CSH Severity
High
Patch available
YES
Number of vulnerabilities 5
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 5 vulnerabilities.


1) Input validation error (CVE-ID: CVE-2026-8388)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to improper input validation in the JavaScript Engine: JIT component when processing crafted JavaScript. A remote attacker can supply specially crafted script content to execute arbitrary code.


2) Incorrect calculation (CVE-ID: CVE-2026-8389)

CWE-ID: CWE-682 - Incorrect Calculation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to JIT miscompilation in the JavaScript Engine: JIT component when processing crafted JavaScript. A remote attacker can supply specially crafted script content to execute arbitrary code.


3) Use-after-free (CVE-ID: CVE-2026-8390)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to use-after-free in the JavaScript: WebAssembly component when processing crafted WebAssembly content. A remote attacker can supply specially crafted WebAssembly content to execute arbitrary code.


4) Input validation error (CVE-ID: CVE-2026-8391)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to an unspecified issue in the JavaScript Engine component. A remote attacker can trick the victim into visiting a specially crafted website and execute arbitrary code on the system.


5) Protection mechanism failure (CVE-ID: CVE-2026-8401)

CWE-ID: CWE-693 - Protection Mechanism Failure

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient implementation of security measures in the Profile Backup component. An attacker can trick the victim into visiting a specially crafted website and bypass sandbox restrictions, leading to remote code execution. 


Remediation

Install update from vendor's website.

References