CVE-2026-55285 Overview
CVE-2026-55285 is an out-of-bounds write vulnerability in the openLogicalChannel function used across multiple Android telephony files. The flaw stems from a missing bounds check and allows a local attacker to escalate privileges without user interaction. Google disclosed the issue in the Android Security Bulletin for September 2026. The vulnerability is classified under CWE-120: Buffer Copy without Checking Size of Input.
Critical Impact
A local application with low privileges can trigger an out-of-bounds write in openLogicalChannel to achieve privilege escalation on affected Android devices, with no user interaction required.
Affected Products
- Android platform components implementing openLogicalChannel across multiple telephony files
- Refer to the Android Security Bulletin September 2026 for the authoritative list of affected versions
- Device builds that have not applied the 2026-09-01 security patch level
Discovery Timeline
- 2026-09-08 - CVE-2026-55285 published to NVD
- 2026-09-08 - Last updated in NVD database
Technical Details for CVE-2026-55285
Vulnerability Analysis
The defect lives in the openLogicalChannel implementation shared across multiple Android telephony source files. The function opens a logical channel to a SIM applet by AID (Application Identifier) and returns channel data to the caller. Because the code path omits a bounds check before writing, attacker-controlled input can write past the end of a fixed-size buffer.
An out-of-bounds write in a privileged Android system service allows an attacker to corrupt adjacent memory in the target process. When the corrupted memory belongs to a component running with elevated privileges, the attacker can gain code execution in that context. The vulnerability requires only local access and low privileges typical of an installed app.
Root Cause
The root cause is a missing input length validation prior to a memory write operation in openLogicalChannel. The function accepts data whose size is not verified against the destination buffer boundary, matching the [CWE-120] buffer copy weakness pattern. Any caller able to invoke the affected telephony code path can supply an oversized payload that overflows the destination.
Attack Vector
Exploitation requires local access to the device and the ability to invoke the vulnerable telephony interface. A malicious application installed on the device can call the exposed API and pass crafted parameters that trigger the out-of-bounds write. User interaction is not required. Successful exploitation yields local privilege escalation, letting the attacker execute code with privileges beyond those originally granted to the app.
No public proof-of-concept exploit is currently referenced in the advisory. Technical specifics are described in the Android Security Bulletin September 2026.
Detection Methods for CVE-2026-55285
Indicators of Compromise
- Unexpected crashes or tombstones in Android telephony processes referencing openLogicalChannel or SIM applet channel APIs
- Newly installed applications requesting or invoking telephony service interfaces without a legitimate use case
- SELinux denials involving telephony components attempting privileged operations outside their normal profile
Detection Strategies
- Monitor Android device logs (logcat, dropbox) for repeated native crashes in telephony services, which may indicate exploitation attempts against openLogicalChannel.
- Inspect installed app inventories for applications requesting access to telephony APIs and correlate against a baseline of trusted apps.
- Track the reported security patch level on managed devices and flag any device below the 2026-09-01 patch level as vulnerable.
Monitoring Recommendations
- Enroll devices in mobile threat defense or MDM solutions that report OS build and monthly patch level.
- Alert on process anomalies inside telephony-related system services, including crash loops and unexpected privilege transitions.
- Correlate suspicious app installations with subsequent telephony service instability across the fleet.
How to Mitigate CVE-2026-55285
Immediate Actions Required
- Apply the Android security patch level 2026-09-01 or later on all managed devices as soon as the OEM makes it available.
- Audit installed applications on affected devices and remove untrusted or unnecessary apps that could deliver the exploit locally.
- Enforce MDM policies that block sideloading and restrict installations to vetted enterprise or Play Store sources.
Patch Information
Google addressed CVE-2026-55285 in the Android Security Bulletin September 2026. Devices must be updated to security patch level 2026-09-01 or later. Availability depends on the device OEM and carrier update cadence; consult the vendor advisory for exact build numbers.
Workarounds
- No official workaround is published. Restrict installation of untrusted applications on unpatched devices as a compensating control.
- Isolate affected devices from sensitive corporate resources until the September 2026 patch level is applied.
- Where feasible, enforce work profile separation to limit the blast radius of a local privilege escalation on personal-owned devices.
# Verify the Android security patch level on a connected device
adb shell getprop ro.build.version.security_patch
# Expected output for patched devices: 2026-09-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
