CVE-2026-32739

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.

CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-835 CWE-835

Affected Products

Vendor	Product	Versions
struktur	libheif	< 1.22.0

References

Advisories & Patches

https://github.com/strukturag/libheif/security/advisories/GHSA-j9g7-q9hv-gq8c https://github.com/strukturag/libheif/security/advisories/GHSA-j9g7-q9hv-gq8c

Exploits

https://github.com/strukturag/libheif/security/advisories/GHSA-j9g7-q9hv-gq8c https://github.com/strukturag/libheif/security/advisories/GHSA-j9g7-q9hv-gq8c

Other References

https://github.com/strukturag/libheif/releases/tag/v1.22.0

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-32739? +

CVE-2026-32739 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-32739? +

CVE-2026-32739 affects products from struktur, specifically: libheif. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-32739? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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