CVE-2026-55270 Overview
CVE-2026-55270 is a permission bypass vulnerability in Google Android affecting the dialInternal function across multiple locations. The flaw stems from a confused deputy condition [CWE-441], where a privileged component acts on behalf of a less-privileged caller without proper authorization checks. A local attacker with low privileges can exploit this issue to escalate privileges without user interaction. The vulnerability affects Android versions 14, 15, 16 (including QPR2 beta builds), and 17. Google addressed the issue in the Android Security Bulletin October 2026.
Critical Impact
Local privilege escalation on Android devices without user interaction, enabling an unprivileged app to gain elevated permissions through the telephony dialInternal code path.
Affected Products
- Google Android 14.0
- Google Android 15.0 and 16.0 (including QPR2 Beta 1, 2, 3)
- Google Android 17.0
Discovery Timeline
- 2026-10-05 - CVE-2026-55270 published to the National Vulnerability Database
- 2026-10-01 - Google published the Android Security Bulletin addressing the issue
- 2026-10-07 - Last updated in the NVD database
Technical Details for CVE-2026-55270
Vulnerability Analysis
The vulnerability resides in the dialInternal function, present in multiple locations within the Android telephony stack. A confused deputy condition [CWE-441] occurs when a privileged process performs an action requested by a less-privileged caller without validating whether that caller is authorized to request the action. In this case, dialInternal executes operations with elevated permissions on behalf of a caller that lacks those permissions.
Exploitation requires only local access and low privileges. An attacker-controlled application installed on the device can invoke the vulnerable code path to perform actions reserved for higher-privileged components. No user interaction is required, which eliminates the need for social engineering as part of the exploitation chain.
Root Cause
The root cause is missing or insufficient permission validation inside dialInternal before it performs privileged operations. The function trusts the context under which it is invoked rather than verifying the identity and permissions of the original caller. This design pattern is the hallmark of a confused deputy flaw: the privileged deputy performs work for a caller whose authorization has not been confirmed.
Attack Vector
The attack vector is local. A malicious application installed on the Android device issues calls that reach dialInternal, triggering privileged behavior that leads to local escalation of privilege. Because exploitation does not require additional execution privileges or user interaction, any installed application capable of reaching the vulnerable interface can attempt the bypass. Technical specifics of the affected code paths are described in the Android Security Bulletin October 2026.
Detection Methods for CVE-2026-55270
Indicators of Compromise
- Unexpected telephony actions initiated by applications that do not hold CALL_PHONE or related permissions.
- Installed applications invoking telephony service bindings without declared permissions in their manifest.
- Anomalous process behavior in system telephony components correlated with activity from third-party apps.
Detection Strategies
- Monitor Android security patch level across the mobile fleet and flag devices still exposed to the October 2026 bulletin.
- Use mobile threat defense telemetry to identify applications attempting privileged telephony operations without the required permissions.
- Correlate privilege-escalation indicators from endpoint telemetry with newly installed or recently updated applications.
Monitoring Recommendations
- Track Android version and patch level inventory in mobile device management (MDM) reporting.
- Review Google Play Protect and MDM alerts for applications flagged as abusing system services.
- Audit side-loaded applications on managed devices and enforce installation restrictions for untrusted sources.
How to Mitigate CVE-2026-55270
Immediate Actions Required
- Apply the Android security patch level dated 2026-10-01 or later on all affected devices.
- Prioritize patch deployment on devices running Android 14, 15, 16, and 17 managed through enterprise MDM.
- Restrict installation of applications from unknown sources until patches are deployed.
Patch Information
Google released fixes as part of the October 2026 Android Security Bulletin. Device manufacturers typically ship these patches in their monthly security update rollout. Administrators should refer to the Android Security Bulletin October 2026 for the full list of fixed CVEs and ensure the 2026-10-01 security patch level is applied.
Workarounds
- No vendor-provided workaround exists; patching is the only effective remediation.
- Enforce MDM policies that block installation of untrusted applications until updates are applied.
- Remove unnecessary third-party applications with access to telephony services on sensitive devices.
# Verify Android security patch level on a connected device
adb shell getprop ro.build.version.security_patch
# Expected output for remediated devices: 2026-10-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.