CVE-2026-21122 Overview
CVE-2026-21122 is an out-of-bounds write vulnerability in libsamsungtts.so, the Samsung text-to-speech shared library used in Samsung mobile devices. The flaw affects versions prior to the Samsung Mobile Release (SMR) October 2026 Release 1 and allows local attackers to execute arbitrary code on affected devices. The vulnerability is classified under CWE-787 and requires local access with no privileges or user interaction to exploit.
Critical Impact
Local attackers can execute arbitrary code within the context of the vulnerable text-to-speech component, potentially compromising device integrity on unpatched Samsung mobile devices.
Affected Products
- Samsung Mobile devices running firmware prior to SMR Oct-2026 Release 1
- libsamsungtts.so text-to-speech shared library
- Samsung Android-based devices integrating the Samsung TTS engine
Discovery Timeline
- 2026-10-12 - CVE CVE-2026-21122 published to the National Vulnerability Database
- 2026-10-14 - Last updated in NVD database
Technical Details for CVE-2026-21122
Vulnerability Analysis
The vulnerability resides in libsamsungtts.so, a native shared library that provides text-to-speech functionality on Samsung mobile devices. An out-of-bounds write condition in the library allows a local attacker to write data beyond the bounds of an allocated buffer. Successful exploitation leads to arbitrary code execution within the process that loads the vulnerable library.
The attack vector is local, meaning the attacker must have the ability to run code or deliver crafted input on the device. The vulnerability does not require authentication or user interaction, lowering the bar for exploitation once local access is obtained. Code execution occurs in the context of the TTS component, which can be leveraged to pivot further into the Android runtime.
Root Cause
The root cause is improper validation of input length or index values before writing to a memory buffer in libsamsungtts.so. Out-of-bounds writes [CWE-787] occur when a program writes past the end, or before the beginning, of an allocated buffer. This typically results from missing bounds checks, incorrect pointer arithmetic, or trust in attacker-controlled size fields. The condition can corrupt adjacent memory structures, including function pointers and heap metadata, enabling control-flow hijack.
Attack Vector
An attacker with local access to the device, such as through a malicious application installed on the handset, can craft input processed by the TTS library to trigger the out-of-bounds write. Because exploitation requires no privileges and no user interaction, a background process or sideloaded application can invoke the vulnerable code path silently. Successful exploitation yields arbitrary code execution within the TTS process context.
No public proof-of-concept exploit code is available for this vulnerability. See the Samsung Mobile Security Update for additional technical context.
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Stop Exploit AttemptsDetection Methods for CVE-2026-21122
Indicators of Compromise
- Unexpected crashes or SIGSEGV signals in processes that load libsamsungtts.so
- Installation of untrusted applications that programmatically invoke Samsung text-to-speech APIs
- Anomalous child processes or memory regions associated with the Samsung TTS service
Detection Strategies
- Monitor Android crash logs and tombstones for faults originating in libsamsungtts.so
- Audit installed applications on Samsung devices for use of TTS APIs combined with suspicious permissions
- Correlate device firmware patch level (ro.build.version.security_patch) against the SMR Oct-2026 baseline across the mobile fleet
Monitoring Recommendations
- Enroll Samsung devices in a mobile device management (MDM) solution that reports security patch level and flags devices below SMR Oct-2026 Release 1
- Review mobile threat defense telemetry for applications abusing accessibility, speech, or TTS-related interfaces
- Track Samsung Mobile Security Bulletin releases for related vulnerabilities in the same component
How to Mitigate CVE-2026-21122
Immediate Actions Required
- Apply the Samsung Mobile Security Maintenance Release for October 2026 (SMR Oct-2026 Release 1) to all affected devices
- Inventory the mobile fleet and prioritize patch deployment for devices currently below the October 2026 patch level
- Restrict installation of untrusted or sideloaded applications on managed Samsung devices
Patch Information
Samsung addressed this vulnerability in SMR Oct-2026 Release 1. Device owners and administrators should install the October 2026 security update as delivered through Samsung's over-the-air update channel or carrier distribution. Full details are available in the Samsung Mobile Security Update bulletin.
Workarounds
- No vendor-supplied workaround is documented; applying SMR Oct-2026 Release 1 is the authoritative remediation
- Limit app installation sources to trusted stores and enforce application allowlists through MDM policy
- Disable or restrict the Samsung TTS engine where business requirements permit, until the patch is applied
# Verify the current Samsung device security patch level via ADB
adb shell getprop ro.build.version.security_patch
# Expected output should be 2026-10-01 or later once SMR Oct-2026 Release 1 is applied
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
