Is CVE-2026-47178 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-47178 being exploited in the wild.

How severe is CVE-2026-47178?

Medium severity, with a CVSS score of 6.1, published 21 July 2026.

Which products and versions are affected?

strukturag libheif 1.19.0 - 1.21.2.

Is there a fix for CVE-2026-47178?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-47178 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-47178?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-47178: Strukturag libheif heap out-of-bounds write in uncompressed tile decoder

CVE-2026-47178 · Severity: medium · CVSS 6.1 · Published 2026-07-21

libheif is a widely used software library for processing HEIF and AVIF image files, commonly found in image viewers, web servers, and photo editing tools. A security flaw allows a specially crafted image file to cause a memory error when opened, potentially leading to a program crash or allowing an attacker to take control of the application. This could impact services that automatically process user-uploaded images, such as social media platforms or cloud storage providers.

Quick answers

Is CVE-2026-47178 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-47178 being exploited in the wild.
How severe is CVE-2026-47178?: Medium severity, with a CVSS score of 6.1, published 21 July 2026.
Which products and versions are affected?: strukturag libheif 1.19.0 - 1.21.2.
Is there a fix for CVE-2026-47178?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-47178 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-47178?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A heap out-of-bounds write exists in libheif's uncompressed 'unci' codec subsystem, specifically within the unc_decoder_component_interleave::decode_tile() function. The vulnerability is caused by an incorrect row offset calculation where full-resolution tile origins are used against halved chroma plane strides in 4:2:0 interleaved images. An attacker can exploit this by providing a crafted HEIF file that overwrites the C++ vtable pointer of an adjacent object. This allows for a controlled indirect call, potentially leading to arbitrary code execution when the next virtual function is dispatched. The issue is fixed in version 1.22.0.

Affected products

strukturag libheif 1.19.0 - 1.21.2

Timeline

2026-05-19: disclosed: Initial disclosure on GitHub
2026-07-21: advisory: NVD publication date

References

https://github.com/strukturag/libheif/security/advisories/GHSA-5x55-x5pf-9c6g

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