What’s Vulnerable › Vulnerabilities

CVE-2026-84446: libheif: Sequence decode timing-table initialization allows non-terminating loops and unbounded memory, bypassing max_sequence_frames

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-21
• Weakness: CWE-835

Description

libheif is a HEIF and AVIF file format decoder and encoder. Prior to 1.23.2, crafted HEIF sequence timing and edit-list data can make Track::init_sample_timing_table() compute a logical m_num_output_samples value that exceeds the uint32_t counters used by Track_Visual::decode_next_image_sample() and Track::get_next_sample_raw_data(). The resulting comparison can never reach the oversized output count, causing non-terminating decode or raw-sample loops and bypassing max_sequence_frames. The same sequence path repeatedly calls Box_stts::get_sample_duration() and allocates Chunk::m_sample_ranges and Track::m_presentation_timeline outside MemoryHandle accounting, allowing severe CPU and memory exhaustion from a small file. This issue is fixed in version 1.23.2.

Affected products

• strukturag libheif: before 1.23.2

References

• https://github.com/strukturag/libheif/commit/3a7a69ae325f652e48c026b8241ab25bedf44d9b
• https://github.com/strukturag/libheif/releases/tag/v1.23.2
• https://github.com/strukturag/libheif/security/advisories/GHSA-xw34-mjcp-jqh8

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