CVE-2025-21009 in libsavsvc.so
Summary
by MITRE • 07/08/2025
Out-of-bounds read in decoding malformed frame header in libsavsvc.so prior to Android 15 allows local attackers to cause memory corruption.
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Analysis
by VulDB Data Team • 07/10/2025
This vulnerability exists in the libsavsvc.so library component of Android systems prior to version 15, representing a critical out-of-bounds read condition that occurs during the processing of malformed frame headers. The flaw manifests when the system attempts to decode frame headers that do not conform to expected specifications, creating a scenario where memory access occurs beyond the allocated buffer boundaries. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can lead to information disclosure, system instability, or potential privilege escalation. The vulnerability is particularly concerning because it affects a core system library that handles video frame processing, making it accessible to local attackers who can exploit the condition through crafted malicious inputs.
The technical implementation of this vulnerability involves the decoding routine within libsavsvc.so failing to properly validate frame header parameters before attempting to read from memory locations. When malformed frame headers are encountered, the system's frame parsing logic does not adequately bounds-check array indices or buffer limits, allowing subsequent memory reads to access unauthorized memory regions. This memory corruption can result in arbitrary code execution or system crashes, depending on the specific memory locations accessed during the out-of-bounds read operation. The vulnerability's impact is amplified by its location within a system service that processes multimedia content, which can be triggered through various legitimate system interactions or malicious inputs.
From an operational perspective, local attackers can exploit this vulnerability without requiring special privileges, making it particularly dangerous in environments where untrusted code execution is possible. The attack vector typically involves crafting specially formatted frame headers that cause the decoding process to reference memory locations outside the intended buffer boundaries. This type of attack aligns with ATT&CK technique T1059.007, which covers the use of scripting languages to execute malicious code, and can be leveraged as part of broader exploitation chains targeting system stability. The vulnerability's presence in Android versions prior to 15 creates a significant risk for devices that have not received the necessary security updates, as these systems remain exposed to potential exploitation.
Mitigation strategies for this vulnerability include immediate deployment of Android security patches that address the out-of-bounds read condition through proper input validation and bounds checking mechanisms. System administrators should prioritize updating all affected Android devices to version 15 or later, where the vulnerability has been resolved through enhanced frame header validation routines. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can help reduce the exploitability of similar vulnerabilities. Organizations should also consider monitoring for suspicious frame header processing activities and implementing network segmentation to limit potential attack surface. The fix typically involves adding comprehensive bounds checking to all memory access operations within the frame header decoding logic, ensuring that array indices and buffer limits are properly validated before any read operations occur. This remediation approach aligns with security best practices outlined in the OWASP Top Ten and follows the principle of least privilege by ensuring that all memory operations are properly constrained and validated.