CVE-2026-84384

High CVSS 7.5

Published 2026-09-18 · last changed 2026-09-18

The fix

We hold no Microsoft remediation data for CVE-2026-84384, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause decompress_brotli() and do_inflate() to grow accumulated output without an effective size limit or MemoryHandle accounting. The brotli path has no output bound, while the zlib path checks only a small temporary buffer in a branch that valid streams do not reach, and overlapping icef units can decompress the same payload repeatedly. HeifContext::interpret_heif_file_images() processes multiple compressed metadata items during file opening, allowing a small file to consume unbounded memory and terminate the process. This issue is fixed in version 1.23.2.

Sources

NVD record for CVE-2026-84384

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