CVE-2026-80583 in Linux
Summary
by MITRE • 08/26/2026
In the Linux kernel, the following vulnerability has been resolved:
ASoC: codecs: lpass-tx-macro: Fix enum kcontrol accesses
The "DEC0 MODE" to "DEC7 MODE" controls are enumerated, but tx_macro_dec_mode_get() and tx_macro_dec_mode_put() access their value through ucontrol->value.integer.value[0] (a long) instead of
ucontrol->value.enumerated.item[0] (an unsigned int).
This same pattern was fixed in the sibling drivers by commit bcfe5f76cc40 ("ASoC: codecs: rx-macro: fix accessing array out of bounds for enum type") and commit 0ea5eff7c606 ("ASoC: codecs: va-macro: fix accessing array out of bounds for enum type"), but tx-macro was missed.
On 64-bit kernels built with CONFIG_SND_CTL_DEBUG, the elem value sanity check catches the 4 bytes written past the enumerated item and every read of these controls fails with -EINVAL:
snd-sm8250 sound: control 2:0:0:DEC0 MODE:0: access overflow
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Analysis
by VulDB Data Team • 08/27/2026
The Linux kernel audio subsystem, specifically the ALSA System on Chip (ASoC) drivers for Qualcomm LPSS codecs, contained a critical type mismatch in how enumerated controls were accessed. The vulnerability resides within the lpass-tx-macro driver, which manages digital microphone interfaces and related audio processing blocks. In this context, several control elements such as DEC0 MODE through DEC7 MODE are defined as enumerated types rather than integer values. Enumerated controls typically represent a selection from a predefined list of options, where each option is identified by an index or identifier stored in the kernel's internal data structures. The correct mechanism for accessing these values involves using the ucontrol->value.enumerated.item array field, which is designed to hold unsigned integers representing indices into the enumeration table. However, the implementation incorrectly utilized ucontrol->value.integer.value[0], a field intended for long integer types that represent arbitrary numeric values rather than enumerated selections.
This type confusion leads directly to an out-of-bounds memory access scenario on 64-bit architectures due to differences in data structure layout and size expectations between the two fields within the union used by ucontrol structures. When the driver attempts to read or write these controls, it interprets the memory location intended for enumerated items as a long integer. On systems where sizeof(long) exceeds sizeof(unsigned int), this results in writing four bytes beyond the allocated space for the enumerated item index. This constitutes an out-of-bounds write vulnerability that can corrupt adjacent kernel memory structures depending on their placement relative to the ucontrol object. The flaw is particularly insidious because it does not always manifest as a crash or immediate system failure under normal conditions, but rather introduces subtle data corruption risks and potential privilege escalation vectors if exploited in conjunction with other vulnerabilities.
The operational impact of this vulnerability varies significantly based on kernel configuration and architecture. On 64-bit kernels compiled with CONFIG_SND_CTL_DEBUG enabled, the Linux kernel's control element sanity checks detect the invalid access pattern immediately. In these configurations, any attempt to read or write the affected controls fails with an -EINVAL error code, effectively preventing exploitation but causing functional degradation for audio applications relying on those specific mode settings. This debug check acts as a safeguard that exposes the underlying memory safety violation without allowing it to proceed silently. However, in production kernels where CONFIG_SND_CTL_DEBUG is disabled, the out-of-bounds write proceeds unchecked, potentially leading to undefined behavior, kernel panics, or security compromises depending on what data resides adjacent to the affected control structure in memory.
This specific flaw mirrors issues previously identified and corrected in sibling drivers such as rx-macro and va-macro via commits bcfe5f76cc40 and 0ea3eff7c606 respectively. The recurrence of this pattern across multiple codec macros highlights a systemic oversight in the initial implementation or maintenance of these audio subsystem components, where developers failed to apply consistent access patterns for enumerated controls across similar hardware interfaces. The fix involves replacing all instances of ucontrol->value.integer.value[0] with ucontrol->value.enumerated.item[0] within the tx_macro_dec_mode_get and tx_macro_dec_mode_put functions. This ensures that the driver correctly interprets the data type and accesses only the memory space allocated for enumerated indices, thereby eliminating the out-of-bounds access vector.
From a security classification perspective, this vulnerability aligns with CWE-125 Out-of-bounds Read and CWE-787 Out-of-bounds Write, as it involves accessing memory outside of intended boundaries due to incorrect type handling within union structures. It also relates to CWE-697 Incorrect Comparison, in the sense that the code incorrectly assumes equivalence between integer and enumerated value storage mechanisms. In terms of MITRE ATT&CK mapping, this flaw could potentially be leveraged for Defense Evasion by masking malicious activity through normal audio control operations if combined with other exploits, or more directly as an Initial Exploitation vector leading to Privilege Escalation via Kernel Memory Corruption (T1068). The vulnerability underscores the importance of strict type safety in kernel-space drivers and highlights how minor deviations from established API patterns can lead to significant memory corruption risks.
Mitigation strategies primarily involve applying the upstream Linux kernel patch that corrects the access method for enumerated controls in the lpass-tx-macro driver. System administrators should ensure their kernels are updated to versions containing this fix, particularly if they operate on 64-bit architectures with high-privilege audio processing workloads. For environments where immediate patching is not feasible, disabling CONFIG_SND_CTL_DEBUG does not mitigate the risk but rather removes the detection mechanism; therefore, monitoring for unusual kernel log entries related to control access overflows can serve as an indicator of attempted exploitation or existing instability caused by this flaw. Additionally, enforcing strict coding standards that mandate explicit casting and type checking when interacting with ucontrol structures across all ASoC codec drivers would prevent similar issues in future development cycles.