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CVE-2026-50142

libheif: unbounded heap allocation in HEIF sequence parser (stsz fixed-size mode missing bound check)

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.23.0
1 proof of concept on GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.0, a crafted HEIF sequence accepted by heif_context_read_from_memory() with the msf1 sequence brand can cause unbounded heap allocation. In libheif/sequences/seq_boxes.cc, Box_stsz::parse() applies max_sequence_frames only to variable-size samples, so fixed-size mode accepts an attacker-controlled sample_count without a bound. In libheif/sequences/track.cc, Track::load() also adds current_sample_idx and samples_per_chunk in 32-bit arithmetic, allowing the consistency check to be bypassed by wraparound. The resulting values reach the Chunk::Chunk() allocation path, which can consume gigabytes of memory and crash or stall the process through memory exhaustion. This issue is fixed in version 1.23.0.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • strukturag libheif

    From 1.19.0 · fixed in 1.23.0

References 4

GitHub · strukturag/libheif

GitHub · MuhammedHussein17/libheif-cve-2026-50142