CVE-2026-21066 in Samsung
Summary
by MITRE • 08/10/2026
Improper input validation in libcodec2_sec_flacdec.so prior to SMR Aug-2026 Release 1 allows local attackers to write out-of-bounds memory.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability resides within the libcodec2_sec_flacdec.so library component, which is part of a broader software ecosystem designed for secure audio decoding operations. This particular flaw represents a classic buffer overflow condition that emerges from inadequate validation of input data structures during FLAC (Free Lossless Audio Codec) file processing. The issue manifests specifically in systems utilizing the SMR security model prior to the August 2026 release cycle, indicating that previous versions contained insufficient bounds checking mechanisms when handling malformed or specially crafted audio data streams.
The technical nature of this vulnerability stems from improper input validation practices that fail to adequately verify array indices and memory access boundaries during FLAC decoding operations. When maliciously constructed audio files are processed through the affected library, the decoder does not properly validate the size parameters of data blocks, leading to scenarios where write operations extend beyond allocated memory regions. This memory corruption vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-787, concerning out-of-bounds writes in heap-based memory structures. The flaw operates at the intersection of software security and audio processing protocols, where standard input sanitization procedures prove insufficient against carefully crafted malicious inputs.
From an operational perspective, this vulnerability presents a significant risk to local attackers who can leverage the out-of-bounds write condition to execute arbitrary code within the context of the affected application. The attack vector requires local system access, making it less immediately dangerous than remote exploits but still highly concerning for environments where privilege escalation is possible or where the vulnerable component operates with elevated permissions. The impact extends beyond simple data corruption, as successful exploitation could lead to complete system compromise through techniques such as return-oriented programming or direct memory manipulation that allows attackers to overwrite critical program structures or inject malicious payloads into running processes.
Mitigation strategies must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities from emerging in future code implementations. The primary recommendation involves applying the security patch released as part of SMR August 2026, which includes enhanced input validation routines and proper bounds checking for all memory allocation operations during FLAC decoding. Additionally, implementing runtime protections such as stack canaries, address space layout randomization, and data execution prevention mechanisms provides defense-in-depth coverage against potential exploitation attempts. Organizations should also consider implementing input sanitization layers that validate audio file headers and metadata before processing, aligning with ATT&CK technique T1059.007 for command and scripting interpreter execution, which emphasizes the importance of validating external inputs to prevent code injection vulnerabilities. Regular security auditing of third-party libraries and maintaining up-to-date software repositories remains essential to prevent similar issues from propagating through complex software ecosystems where multiple components depend on vulnerable foundational elements.