CVE-2026-84450
libheif: `clap` + oversized `ispe` aborts on an assert in `Fraction::Fraction` (incomplete fix for CVE-2026-62289)
Description
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.
INFO
Published Date :
Sept. 18, 2026, 4:17 p.m.
Last Modified :
Sept. 21, 2026, 9:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update libheif to version 1.23.3.
- Rebuild applications using the updated library.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-84450.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-84450 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-84450
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-84450 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-84450 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 21, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-84450', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-18T19:30:30.489038Z'} -
New CVE Received by [email protected]
Sep. 18, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L Added CWE CWE-617 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/84xxx/CVE-2026-84450.json">CVE-2026-84450</a> Added Reference https://github.com/strukturag/libheif/commit/1c2df9c0e814f89716f3a4d85a444b2dbc63ad69 Added Reference https://github.com/strukturag/libheif/releases/tag/v1.23.3 Added Reference https://github.com/strukturag/libheif/security/advisories/GHSA-gh5q-69gg-c964