CVE-2026-117958
Received Received - Intake

Firefox Site Isolation Bypass in Networking HTTP

Publication date: 2026-10-27

Last updated on: 2026-10-27

Assigner: Mozilla Corporation

Description
Site isolation issue in the Networking: HTTP component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-27
Last Modified
2026-10-27
Generated
2026-10-27
AI Q&A
2026-10-27
EPSS Evaluated
N/A
NVD
CVE-2026-117958
EUVD
EUVD-2026-110989

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a site isolation issue in Firefox's Networking: HTTP component. Site isolation is a security feature that separates different websites to prevent malicious sites from accessing data from other sites. A flaw in this component could allow unauthorized access or data leakage between sites.

Impact Analysis

If exploited, this vulnerability could allow an attacker to access sensitive data from other websites you are logged into, such as cookies, session tokens, or personal information. This could lead to account hijacking, data theft, or unauthorized actions on your behalf.

Compliance Impact

This vulnerability could lead to unauthorized access to personal data, violating GDPR's data protection principles or HIPAA's safeguards for protected health information. Organizations using affected Firefox versions may face compliance breaches, legal penalties, or reputational damage.

Mitigation Strategies

Update Firefox to version 159 or later and Firefox ESR to version 153.6 or later to address the site isolation issue in the Networking: HTTP component.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-117958. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart