CVE-2026-33164 in libde265
Summary
by MITRE • 03/20/2026
libde265 is an open source implementation of the h.265 video codec. Prior to version 1.0.17, a malformed H.265 PPS NAL unit causes a segmentation fault in pic_parameter_set::set_derived_values(). This issue has been patched in version 1.0.17.
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Analysis
by VulDB Data Team • 03/27/2026
The vulnerability identified as CVE-2026-33164 affects libde265, an open source implementation of the h.265 video codec that is widely used in multimedia applications and streaming platforms. This issue represents a critical security flaw that could potentially be exploited to cause denial of service conditions in systems relying on the library for video processing. The vulnerability specifically targets the parsing and handling of H.265 Picture Parameter Set (PPS) Network Abstraction Layer (NAL) units, which are essential components for video decoding operations. The affected library version prior to 1.0.17 contains a memory management error that manifests when processing malformed PPS NAL units, leading to system instability and potential application crashes.
The technical flaw occurs within the pic_parameter_set::set_derived_values() function where the library fails to properly validate incoming PPS NAL unit data structures. When a malformed PPS NAL unit is encountered, the function attempts to access memory locations that have not been properly initialized or allocated, resulting in a segmentation fault that terminates the executing process. This type of vulnerability falls under the Common Weakness Enumeration category of improper input validation, specifically CWE-121, which deals with stack-based buffer overflow conditions. The issue demonstrates poor defensive programming practices where the library does not implement adequate bounds checking or error handling for malformed input data that could be encountered in real-world streaming scenarios.
The operational impact of this vulnerability extends beyond simple application crashes to potentially affect broader system stability in environments where libde265 is integrated into critical multimedia processing pipelines. Attackers could exploit this weakness by crafting malicious video streams containing malformed PPS NAL units, which when processed by vulnerable applications would cause segmentation faults and system disruptions. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or application crashes. The vulnerability could be particularly dangerous in streaming services, video conferencing platforms, or content delivery networks where continuous availability is critical, as it could enable attackers to disrupt video services and potentially cause cascading failures in dependent systems.
Mitigation strategies for CVE-2026-33164 require immediate deployment of libde265 version 1.0.17, which includes proper input validation and error handling for malformed PPS NAL units. Organizations should conduct comprehensive vulnerability assessments to identify all systems and applications utilizing the affected library, implementing patch management processes to ensure timely updates. Additional defensive measures include implementing network segmentation to limit exposure, deploying intrusion detection systems to monitor for suspicious video stream patterns, and establishing robust input validation mechanisms at network boundaries. Security teams should also consider implementing application whitelisting policies to restrict execution of untrusted video content and maintain detailed monitoring logs to detect potential exploitation attempts. The fix addresses the root cause by introducing proper bounds checking and memory allocation validation within the affected function, preventing the segmentation fault condition that previously occurred during malformed data processing.