SB2026051929 - Multiple vulnerabilities in Mozilla Firefox ESR 115
Published: May 19, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 7 vulnerabilities.
1) Out-of-bounds read (CVE-ID: CVE-2026-8946)
CWE-ID: CWE-125 - Out-of-bounds read
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 incorrect boundary conditions in the Audio/Video: Web Codecs component when processing crafted web content. A remote attacker can cause the browser to process specially crafted content to execute arbitrary code.
User interaction is required to visit a specially crafted website or URL.
2) 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.
3) Use-after-free (CVE-ID: CVE-2026-8947)
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 DOM: Bindings (WebIDL) component when processing crafted web content. A remote attacker can cause the browser to process specially crafted content to execute arbitrary code.
User interaction is required to visit a specially crafted website or URL.
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.
6) Use-after-free (CVE-ID: CVE-2026-8953)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to escape the sandbox.
The vulnerability exists due to use-after-free in the Disability Access APIs component when processing crafted web content. A remote attacker can trigger the flaw to escape the sandbox.
User interaction is required to visit a specially crafted website or URL.
7) Buffer overflow (CVE-ID: CVE-2026-8975)
CWE-ID: CWE-119 - Memory corruption
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 memory corruption in multiple components when processing crafted web content. A remote attacker can cause the browser to process specially crafted content to execute arbitrary code.
User interaction is required to visit a specially crafted website or URL.
Remediation
Install update from vendor's website.