CVE-2026-6756: 
NixOS vulnerability analysis and mitigation

CVE-2026-6756 is a mitigation bypass vulnerability in Firefox for Android, discovered and disclosed on April 21, 2026, as part of Mozilla Foundation Security Advisory 2026-30. It affects all versions of Firefox for Android prior to 150.0. The vulnerability was reported by security researchers Hafiizh & Kang Ali and is classified with a CVSS v3.1 base score of 7.5 (High), with an integrity-only impact and no authentication required (Mozilla Advisory, Github Advisory).

The vulnerability is classified under CWE-807 (Reliance on Untrusted Inputs in a Security Decision) and CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), indicating that Firefox for Android improperly relies on attacker-controllable inputs when making security decisions, allowing a security mitigation to be bypassed (Mozilla Advisory, Github Advisory). The attack vector is network-based, requires no privileges and no user interaction, and has low attack complexity. The specific technical details of the bypass mechanism are not publicly disclosed, as the Mozilla Bugzilla entry (Bug 1992585) requires permissions to access (Mozilla Advisory).

Successful exploitation of this vulnerability results in a high integrity impact on the affected Android device, allowing an unauthenticated remote attacker to bypass security mitigations in Firefox for Android. There is no direct confidentiality or availability impact as assessed by CVSS, but the mitigation bypass could enable further attacks or unauthorized modifications to browser behavior or data. The scope is limited to the affected Firefox for Android application and does not indicate lateral movement or cross-component compromise (Github Advisory, Mozilla Advisory).

No public proof-of-concept exploit code or evidence of in-the-wild exploitation has been reported for CVE-2026-6756. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term (Github Advisory). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no threat actor attribution has been identified.

Mozilla has addressed this vulnerability in Firefox 150 for Android, released on April 21, 2026. Users should update Firefox for Android to version 150.0 or later via the Google Play Store or their device's app update mechanism. No specific configuration-based workaround has been published; upgrading to the patched version is the recommended and only confirmed remediation (Mozilla Advisory).

The CIS (Center for Internet Security) published an advisory noting that multiple vulnerabilities in Mozilla products, including CVE-2026-6756, could allow for arbitrary code execution and recommended prompt patching. Security news outlets including GBHackers and CyberPress covered the Firefox 150 release and its security fixes broadly, though CVE-2026-6756 was not individually highlighted due to its moderate impact rating compared to higher-severity issues in the same release (Mozilla Advisory).