Executive Summary

This vulnerability is a heap-buffer-overflow read found in libaom, the reference AV1 codec implementation. It occurs because of a missing bounds check in the SVC (Scalable Video Coding) layer ID control function, which allows setting a spatial_layer_id that exceeds the configured number of layers.

When this happens, the encoder reads out-of-bounds memory on the heap by approximately 40,728 bytes while computing a layer context array index. This can lead to unintended behavior such as leaking heap contents or causing a segmentation fault.

An attacker who can influence SVC encoder parameters in a network-facing service could exploit this vulnerability.

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Compliance Impact

This vulnerability allows an attacker to cause information disclosure by leaking adjacent heap contents or to cause denial of service by triggering a segmentation fault. Information disclosure vulnerabilities can potentially lead to unauthorized access to sensitive data, which may impact compliance with data protection regulations such as GDPR or HIPAA if the leaked data includes personal or protected health information.

However, the provided information does not specify the exact nature of the data that could be leaked or whether it includes regulated personal or health information. Therefore, the direct impact on compliance with standards like GDPR or HIPAA depends on the context in which libaom is used and the type of data processed.

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Impact Analysis

This vulnerability can impact you in two main ways:

• Information disclosure: An attacker could exploit the out-of-bounds read to leak adjacent heap contents, potentially exposing sensitive data.
• Denial of service: If the out-of-bounds read hits unmapped memory, it can cause a segmentation fault, crashing the application or service using the vulnerable codec.

The vulnerability is exploitable from any application using the SVC encoder with untrusted layer_id input, especially in network-facing services.

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Detection Guidance

This vulnerability arises from a missing bounds check in the SVC layer ID control function of libaom, which can be exploited by setting invalid spatial_layer_id values. Detection involves verifying if the libaom version in use is vulnerable (prior to v3.14.0) and monitoring applications that use the SVC encoder for abnormal crashes or information leaks.

Since the vulnerability is triggered by invalid spatial or temporal layer IDs, one way to detect exploitation attempts is to monitor logs or application behavior for errors related to invalid parameters or segmentation faults.

There are no specific commands provided in the resources to detect this vulnerability directly on the network or system.

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Mitigation Strategies

The primary mitigation step is to upgrade libaom to version 3.14.0 or later, where the vulnerability has been fixed by adding bounds validation to the spatial and temporal layer ID controls.

If upgrading immediately is not possible, restrict or validate any untrusted input that can influence SVC encoder parameters, especially the spatial_layer_id and temporal_layer_id values, to ensure they do not exceed configured limits.

Monitor applications using libaom for crashes or unusual behavior that might indicate exploitation attempts.

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