libheif 1.23.0 - Unsafe heif_context_read_from_memory Crash
CVE-2026-62377 Published on August 18, 2026
libheif: Reachable assertion in HeifContext::get_track() aborts on a valid-but-empty HEIF sequence file (context.cc:2110)
libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.
Vulnerability Analysis
CVE-2026-62377 can be exploited with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Types
What is an assertion failure Vulnerability?
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
CVE-2026-62377 has been classified to as an assertion failure vulnerability or weakness.
Use of Uninitialized Resource
The software uses or accesses a resource that has not been initialized. When a resource has not been properly initialized, the software may behave unexpectedly. This may lead to a crash or invalid memory access, but the consequences vary depending on the type of resource and how it is used within the software.
Products Associated with CVE-2026-62377
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