Medium 4.3Published Sep 18, 2026

CVE-2026-84450libheif: `clap` + oversized `ispe` aborts on an assert in `Fraction::Fraction` (incomplete fix for CVE-2026-62289)

Updated under an hour ago (2026-10-19 10:23 UTC)

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Every CVE for strukturag libheif

Exploited in the last 30 days

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.3, a crafted image item containing a clap property and an ispe width or height greater than INT32_MAX + 1 can reach crop calculations through heif_image_handle_get_image_tiling(). Box_clap::left_rounded() or Box_clap::top_rounded() passes the image dimension minus one to Fraction::Fraction(), whose uint32_t constructor uses an assertion as input validation, causing assert-enabled builds to abort. Release builds can instead compute invalid crop geometry, and the tiling API returns dimensions that the normal decode security limits reject. This issue is fixed in version 1.23.3.

CVSS: 4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-617
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

strukturag libheif strukturag:libheif (from the name)	from 1.19.0, < 1.23.3	CNA record

References

https://github.com/strukturag/libheif/security/advisories/GHSA-gh5q-69gg-c964x-refsource-confirm
https://github.com/strukturag/libheif/commit/1c2df9c0e814f89716f3a4d85a444b2dbc63ad69x-refsource-misc
https://github.com/strukturag/libheif/releases/tag/v1.23.3x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.