CVE-2026-32739: struktur libheif Infinite Loop

Vulnerability summary

CVE-2026-32739 is a medium (CVSS 6.5) Infinite Loop vulnerability in struktur libheif. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 31.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 19-05-2026
   PublishedVulnerability first disclosed.
2. 20-05-2026
   Last modifiedVulnerability information updated.

Description

libheif is a HEIF and AVIF file format decoder and encoder. In versions 1.21.2 and below, a crafted 800-byte HEIF sequence file causes an infinite loop in Box_stts::get_sample_duration(), consuming 100% CPU indefinitely with zero progress, leading to DoS. The loop has no iteration limit or timeout and is triggered during file open (parsing) - before any user interaction or image decoding. The process stays alive (no crash, no error logged), making it invisible to crash-based monitoring. This issue has been fixed in version 1.22.0.

• 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.