CVE-2026-84446: strukturag libheif Infinite Loop

Vulnerability summary

CVE-2026-84446 is a high (CVSS 7.5) Infinite Loop vulnerability in strukturag libheif. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.4% of scored vulnerabilities.

Timeline

1. 18-09-2026
   PublishedVulnerability first disclosed.
2. 21-09-2026
   Last modifiedVulnerability information updated.

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.

• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.