Vulnerability in Struktur Libheif
CVE-2026-32739
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (31.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Struktur Libheif
- Strukturag Libheif — versions < 1.22.0
Weakness classification (CWE)
References
- github.com/strukturag/libheif/security/advisories/GHSA-j9g7-q9hv-gq8c (Exploit, Vendor Advisory)
- github.com/strukturag/libheif/releases/tag/v1.22.0 (Release Notes)
Frequently asked questions
- What is CVE-2026-32739?
- CVE-2026-32739 is a medium-severity vulnerability in Struktur Libheif, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2026-05-19.
- How severe is CVE-2026-32739?
- Medium severity. CVSS v3 base score is 6.5 out of 10.