CVE-2026-55359: Permission Bypass Privilege Escalation

CVE-2026-55359 Overview

CVE-2026-55359 is a permission bypass vulnerability affecting Android, disclosed in the Android Security Bulletin for September 2026. The flaw stems from a logic error present in multiple code locations that permits improper enforcement of permission checks [CWE-693]. An attacker with local access and low privileges can exploit the weakness to achieve local escalation of privilege. Exploitation requires User-level execution privileges but no user interaction, allowing a malicious application already installed on the device to elevate its rights silently.

Critical Impact
A malicious local application can bypass Android permission enforcement to escalate privileges, gaining unauthorized access to protected data, components, or system functions without user interaction.

Affected Products

Android (Pixel devices per the September 2026 Pixel bulletin)
Refer to the Android Security Bulletin September 2026 for the complete list of affected components and build fingerprints

Discovery Timeline

2026-09-15 - CVE-2026-55359 published to the National Vulnerability Database
2026-09-17 - Last updated in the NVD database

Technical Details for CVE-2026-55359

Vulnerability Analysis

The vulnerability is classified under [CWE-693] Protection Mechanism Failure. The advisory states that a logic error in multiple code locations causes Android's permission enforcement to be bypassed under specific conditions. The flaw is exploitable locally, meaning the attacker must already have code execution on the device, typically through an installed application running with standard user-level privileges.

Successful exploitation results in local escalation of privilege, with high impact to confidentiality, integrity, and availability. Because no user interaction is required, a malicious app can trigger the bypass silently in the background. This makes the flaw attractive for chaining with earlier-stage vulnerabilities such as remote code execution in a sandboxed process.

The EPSS probability is 0.126%, reflecting a low predicted likelihood of widespread exploitation activity in the near term. However, local privilege escalation issues on mobile platforms are routinely weaponized by commercial spyware vendors.

Root Cause

The root cause is a logic error in the code that governs permission checks across multiple locations. Instead of a missing check, the affected routines evaluate permissions in a way that allows the check to be satisfied under states the developers did not anticipate. Android's advisory does not publicly disclose the specific components involved beyond the reference to the September 2026 Pixel bulletin.

Attack Vector

The attack vector is local. An unprivileged application installed on the device invokes the affected interface or component and exercises the code path where the permission check is incorrectly evaluated. Because the flaw is a logic error rather than a memory corruption bug, exploitation does not require crafted native payloads and is likely to be reliable across affected builds.

No public proof-of-concept exploit code is available. Detailed technical mechanics are described in the Android Security Bulletin September 2026.

Detection Methods for CVE-2026-55359

Indicators of Compromise

Applications requesting or successfully accessing permission-protected APIs, content providers, or system services that they have not been granted at install time
Unexpected privilege elevation events in Android logs (logcat, dropbox, or dumpsys) originating from third-party UIDs
Newly sideloaded or recently updated applications immediately preceding anomalous system-level activity

Detection Strategies

Monitor mobile device management (MDM) telemetry for devices running Android builds older than the September 2026 security patch level
Correlate application install events with subsequent access to sensitive APIs or protected components
Review installed application inventories for apps from untrusted sources or with recent permission scope changes

Monitoring Recommendations

Enforce a minimum Android security patch level of 2026-09-01 or later through MDM compliance policies
Ingest mobile threat defense telemetry into a centralized data lake for correlation with endpoint and identity signals
Alert on installations of applications outside approved enterprise app catalogs on managed devices

How to Mitigate CVE-2026-55359

Immediate Actions Required

Apply the September 2026 Android security patch (patch level 2026-09-01 or later) to all managed Pixel and Android devices
Audit the installed application inventory on affected devices and remove applications from untrusted sources
Enforce MDM policies that block devices below the required patch level from accessing corporate resources

Patch Information

Google addressed CVE-2026-55359 in the September 2026 Android Security Bulletin. Devices with a security patch level of 2026-09-01 or later contain the fix. Consult the Android Security Bulletin September 2026 for build fingerprints and OEM-specific rollout details.

Workarounds

No official workaround is published; patching to the September 2026 security patch level is the required remediation
Restrict installation of applications to vetted enterprise catalogs and disable installation from unknown sources
Enroll devices in mobile threat defense and MDM programs to enforce patch compliance and monitor for anomalous privilege use