CVE-2023-54245 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds
When we run syzkaller we get below Out of Bound. "KASAN: slab-out-of-bounds Read in regcache_flat_read"
Below is the backtrace of the issue:
dump_backtrace+0x0/0x4c8 show_stack+0x34/0x44 dump_stack_lvl+0xd8/0x118 print_address_description+0x30/0x2d8 kasan_report+0x158/0x198 __asan_report_load4_noabort+0x44/0x50 regcache_flat_read+0x10c/0x110 regcache_read+0xf4/0x180 _regmap_read+0xc4/0x278 _regmap_update_bits+0x130/0x290 regmap_update_bits_base+0xc0/0x15c snd_soc_component_update_bits+0xa8/0x22c snd_soc_component_write_field+0x68/0xd4 tx_macro_digital_mute+0xec/0x140
Actually There is no need to have decimator with 32 bits. By limiting the variable with short type u8 issue is resolved.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability CVE-2023-54245 represents a critical memory safety issue within the Linux kernel's audio subsystem, specifically affecting the tx-macro codec driver. This flaw manifests as a slab-out-of-bounds read condition that was identified through automated fuzzing with syzkaller, a sophisticated kernel fuzzer designed to discover memory corruption vulnerabilities. The issue occurs within the audio subsystem's register cache management functions, where improper memory access patterns can lead to unauthorized data reads beyond allocated memory boundaries. The vulnerability specifically targets the regcache_flat_read function which is responsible for reading register values from a flat register cache structure, creating a potential attack vector that could be exploited to gain unauthorized access to kernel memory regions.
The technical root cause of this vulnerability stems from an improper data type declaration within the tx-macro codec driver implementation. The code was utilizing a 32-bit variable where only an 8-bit value was appropriate, creating an unnecessary memory footprint that exceeded the bounds of the allocated slab memory. This type mismatch directly violates the principle of least privilege and proper memory allocation practices that are fundamental to kernel security. The backtrace clearly demonstrates the execution path leading to the memory violation, showing how the error propagates through the audio subsystem's register cache layer, ultimately originating from the snd_soc_component_write_field function that handles register field updates. This particular code path involves updating codec register bits through the regmap subsystem, where the improper variable sizing creates a scenario where memory reads extend beyond the intended buffer boundaries.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential pathway for privilege escalation and system stability compromise within the Linux audio subsystem. When exploited, this out-of-bounds read condition could allow attackers to access sensitive kernel memory, potentially revealing confidential information or enabling further exploitation techniques that align with the attack patterns described in the ATT&CK framework under privilege escalation and defense evasion techniques. The vulnerability is particularly concerning because it affects the audio codec driver layer, which is frequently accessed during normal system operation, making it a persistent threat vector. The KASAN (Kernel Address Sanitizer) detection mechanism properly identifies this issue, demonstrating that the kernel's built-in memory safety checks can detect such violations, though the underlying code structure requires remediation to prevent exploitation.
The fix for CVE-2023-54245 involves a straightforward but critical code modification that changes the data type of a variable from a 32-bit representation to a proper 8-bit unsigned integer type. This change aligns with the CWE (Common Weakness Enumeration) classification for improper integer type usage, specifically CWE-704 which addresses incorrect type usage in programming constructs. The solution directly addresses the root cause by ensuring that the variable size matches the actual data requirements, eliminating the possibility of out-of-bounds memory access. This remediation approach follows security best practices by minimizing the attack surface through proper type safety and memory boundary enforcement. The fix demonstrates the importance of adhering to proper data type declarations in kernel code, where even seemingly minor type mismatches can create significant security implications. Organizations should prioritize applying this patch immediately, as it resolves a memory safety issue that could potentially be exploited to compromise system integrity and audio subsystem functionality. The resolution also highlights the value of automated testing tools like syzkaller in identifying subtle memory safety issues that might otherwise remain undetected in traditional testing scenarios.