CVE-2026-6764 Overview
CVE-2026-6764 is a boundary condition vulnerability affecting the DOM: Device Interfaces component in Mozilla Firefox and Thunderbird. The flaw stems from incorrect boundary conditions that could allow attackers to manipulate memory operations, potentially leading to data integrity issues and limited denial of service conditions. This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer).
Critical Impact
An attacker exploiting this vulnerability via network-based attacks could compromise data integrity and cause service disruption in affected Mozilla products without requiring authentication or user interaction.
Affected Products
- Mozilla Firefox versions prior to 150
- Mozilla Firefox ESR versions prior to 140.10
- Mozilla Thunderbird versions prior to 150
- Mozilla Thunderbird ESR versions prior to 140.10
Discovery Timeline
- April 21, 2026 - CVE-2026-6764 published to NVD
- April 22, 2026 - Last updated in NVD database
Technical Details for CVE-2026-6764
Vulnerability Analysis
The vulnerability exists within the DOM: Device Interfaces component of Mozilla's browser engine. Incorrect boundary conditions in this component can lead to improper restriction of operations within a memory buffer. When the DOM: Device Interfaces component processes certain input, it fails to properly validate boundary conditions, potentially allowing operations to occur outside the intended memory boundaries.
This type of boundary condition error (CWE-119) typically occurs when code manipulates memory without proper checks on the size or boundaries of the data being processed. In this case, the DOM: Device Interfaces component does not adequately enforce limits, which could result in memory operations affecting adjacent memory regions.
Root Cause
The root cause of CVE-2026-6764 lies in insufficient validation of boundary conditions within the DOM: Device Interfaces component. The affected code paths fail to properly check that memory operations remain within expected bounds before execution. This oversight allows potential out-of-bounds access during DOM operations related to device interfaces, which could lead to data corruption or application instability.
Attack Vector
The vulnerability is exploitable via network-based attack vectors. An attacker could craft malicious web content that triggers the improper boundary conditions when processed by the DOM: Device Interfaces component. The attack does not require user interaction beyond visiting a malicious or compromised website.
The attack does not require authentication or elevated privileges. When a user navigates to a page containing malicious content designed to trigger this vulnerability, the browser's DOM engine may process the content in a way that violates memory boundaries. The impact includes potential modification of data integrity and limited availability disruption. For detailed technical analysis, see the Mozilla Bug Report #2022162.
Detection Methods for CVE-2026-6764
Indicators of Compromise
- Unexpected browser crashes or instability when visiting specific web pages
- Abnormal memory consumption patterns in Firefox or Thunderbird processes
- Application error logs indicating DOM-related exceptions or boundary errors
- Unusual behavior when web pages interact with device-related JavaScript APIs
Detection Strategies
- Monitor browser process behavior for anomalous memory access patterns
- Implement network-level detection for malicious web content targeting DOM interfaces
- Deploy endpoint detection and response (EDR) solutions to identify exploitation attempts
- Review browser crash reports for patterns indicating boundary condition violations
Monitoring Recommendations
- Enable enhanced logging for DOM-related operations in enterprise browser deployments
- Configure security information and event management (SIEM) systems to alert on browser process anomalies
- Implement network traffic analysis to detect potential exploit delivery attempts
- Monitor endpoint telemetry for signs of browser-based attacks
How to Mitigate CVE-2026-6764
Immediate Actions Required
- Update Mozilla Firefox to version 150 or later immediately
- Update Mozilla Firefox ESR to version 140.10 or later
- Update Mozilla Thunderbird to version 150 or later
- Update Mozilla Thunderbird ESR to version 140.10 or later
- Verify updates have been applied across all enterprise endpoints
Patch Information
Mozilla has released security updates addressing CVE-2026-6764 across multiple product lines. The patches are documented in the following security advisories:
- Mozilla Security Advisory MFSA-2026-30
- Mozilla Security Advisory MFSA-2026-32
- Mozilla Security Advisory MFSA-2026-33
- Mozilla Security Advisory MFSA-2026-34
Organizations should prioritize patching based on their risk assessment and exposure. The fix addresses the boundary condition validation logic in the DOM: Device Interfaces component to ensure proper memory bounds checking.
Workarounds
- Restrict browsing to trusted websites until patches can be applied
- Consider using browser isolation technologies for high-risk browsing scenarios
- Implement content security policies (CSP) to limit JavaScript execution on untrusted content
- Deploy web filtering to block access to known malicious domains
# Verify Firefox version on Linux/macOS
firefox --version
# Expected output: Mozilla Firefox 150.0 or higher
# Verify Thunderbird version
thunderbird --version
# Expected output: Mozilla Thunderbird 150.0 or higher
# For enterprise deployments, check ESR versions
firefox-esr --version
# Expected output: Mozilla Firefox 140.10 ESR or higher
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
