CVE-2026-20462 Overview
CVE-2026-20462 is a heap buffer overflow vulnerability in the MediaTek Telephony component that can lead to local memory corruption. Successful exploitation allows a local attacker with System privilege to escalate privileges further on affected devices. The flaw does not require user interaction, which increases risk on devices where an adversary has already established a System-level foothold. MediaTek tracks the fix under Patch ID ALPS11006447 and Issue ID MSV-7871. The vulnerability is classified under CWE-122: Heap-based Buffer Overflow.
Critical Impact
A local attacker with System privilege can trigger heap memory corruption in the Telephony stack to achieve additional privilege escalation without any user interaction.
Affected Products
- MediaTek chipsets containing the vulnerable Telephony component
- Android devices integrating affected MediaTek firmware
- Vendor OEM builds referenced in the MediaTek July 2026 Security Bulletin
Discovery Timeline
- 2026-07-01 - CVE-2026-20462 published to NVD
- 2026-07-02 - Last updated in NVD database
Technical Details for CVE-2026-20462
Vulnerability Analysis
The vulnerability resides in the Telephony component shipped with MediaTek platform firmware. A heap buffer overflow condition allows an attacker to write beyond the bounds of a heap-allocated buffer during Telephony message or data processing. Corrupting adjacent heap metadata or object pointers enables an attacker to influence control flow within the privileged process handling telephony operations.
Because exploitation requires local access and pre-existing System privilege, the flaw is a post-compromise escalation primitive rather than an initial access vector. The absence of user interaction makes the vulnerability suitable for chaining with earlier stages of a mobile exploit chain. Attackers can use it to move from a compromised System context toward higher-privileged native services or kernel-adjacent components.
Root Cause
The defect is a heap-based buffer overflow [CWE-122] within the Telephony code path. The affected routine fails to correctly validate the size of attacker-influenced input before copying it into a fixed-size heap buffer. Insufficient bounds checking during allocation or copy operations allows adjacent heap regions to be overwritten. MediaTek addresses the flaw in patch ALPS11006447 tracked under issue MSV-7871.
Attack Vector
Exploitation is local and requires an attacker who has already obtained System privilege on the target device. From that context, the attacker sends crafted input to the vulnerable Telephony interface to trigger the overflow. No user interaction is required. Successful exploitation results in memory corruption inside the Telephony process, which the attacker leverages for further privilege escalation on the device.
No verified proof-of-concept code is publicly available. Refer to the MediaTek Security Bulletin - July 2026 for vendor-provided technical details.
Detection Methods for CVE-2026-20462
Indicators of Compromise
- Unexpected crashes, tombstones, or SIGSEGV signals originating from the Telephony process on MediaTek-based devices
- Kernel or logcat entries indicating heap corruption, abort messages, or SELinux denials associated with telephony services
- Presence of unauthorized native binaries or scripts executing under System or telephony service contexts
Detection Strategies
- Baseline Telephony process behavior on managed mobile fleets and alert on abnormal restart patterns or repeated native crashes
- Correlate device attestation failures and MediaTek firmware patch level mismatches against the July 2026 security bulletin
- Inspect Android bugreport artifacts for heap corruption signatures in the telephony service after suspected compromise
Monitoring Recommendations
- Enforce mobile device management (MDM) policies that flag devices missing the July 2026 MediaTek security patch level
- Ingest mobile telemetry into a centralized data lake to identify anomalous privilege transitions on Android endpoints
- Track outbound network activity from managed devices for post-exploitation command-and-control indicators
How to Mitigate CVE-2026-20462
Immediate Actions Required
- Apply the OEM firmware update that incorporates MediaTek patch ALPS11006447 on all affected devices
- Verify Android security patch level reflects the July 2026 MediaTek bulletin after deployment
- Restrict installation of untrusted applications on managed devices to reduce the likelihood of an attacker obtaining System privilege
Patch Information
MediaTek released the fix under Patch ID ALPS11006447 and Issue ID MSV-7871. Device OEMs must integrate this patch into their firmware builds and distribute it through their standard Android update channels. Consult the MediaTek Security Bulletin - July 2026 for the complete list of affected chipsets and vendor guidance.
Workarounds
- No vendor-supplied workaround exists; patching is the only supported remediation
- Limit exposure by enforcing least privilege on installed applications and disabling sideloading through MDM policy
- Isolate devices that cannot receive the patch from sensitive corporate networks and data until firmware is updated
# Verify Android security patch level on a managed device
adb shell getprop ro.build.version.security_patch
# Confirm MediaTek vendor patch level where exposed by the OEM
adb shell getprop ro.vendor.build.security_patch
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
