# CVE-2026-47178: libheif has Heap Out Of Bounds Write in unci subsystem

> A crafted HEIF file triggers a heap out-of-bounds write in libheif, allowing attackers to overwrite vtable pointers and achieve arbitrary code execution.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Jul 2026
- **Updated:** 22 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-47178, ECHO-8449-98f8-ce75, GHSA-5x55-x5pf-9c6g, JLSEC-2026-1095, ROOT-OS-DEBIAN-11-CVE-2026-47178, UBUNTU-CVE-2026-47178, USN-8479-1

## What is CVE-2026-47178?

CVE-2026-47178 is a medium-severity memory corruption vulnerability in strukturag libheif, published on 21 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

libheif is a HEIF and AVIF file format decoder and encoder. In versions 1.19.0 through 1.21.2, a crafted HEIF file (uncompressed `unci` codec, tiled, component-interleaved, 4:2:0) triggers a heap out-of-bounds write in libheif's uncompressed tile decoder. The write overwrites the C++ vtable pointer of an adjacent `unc_decoder_component_interleave` object; the next virtual call dispatches to an attacker-chosen address. Version 1.22.0 patches the issue.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-47178?

It affects 1 product.


Products: Struktur Libheif.

## How do I fix CVE-2026-47178?

Upgrade to a fixed version.

## Is CVE-2026-47178 being exploited?

There is no known exploitation of CVE-2026-47178 in the wild and no public exploit code.

## Other vulnerabilities in strukturag libheif

- [CVE-2026-32740](https://insights.sbomify.com/CVE-2026-32740/): libheif: Heap-Buffer-Overflow Write in Grid Tile Chroma Compositing (high 8.8)
- [CVE-2023-49460](https://insights.sbomify.com/CVE-2023-49460/): Null dereference in n/a (high 8.8)
- [CVE-2023-49462](https://insights.sbomify.com/CVE-2023-49462/): Null dereference in n/a (high 8.8)
- [CVE-2023-49463](https://insights.sbomify.com/CVE-2023-49463/): Null dereference in n/a (high 8.8)
- [CVE-2023-49464](https://insights.sbomify.com/CVE-2023-49464/): Null dereference in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47178 and fix it if it is affected.

What it is: CVE-2026-47178 is a medium-severity memory corruption vulnerability in strukturag libheif, published on 21 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-47178 in the wild and no public exploit code.

Affected product: strukturag libheif. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-47178/ (Markdown: https://insights.sbomify.com/CVE-2026-47178/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47178
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47178
- OSV: https://osv.dev/vulnerability/CVE-2026-47178

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47178/
Summaries are generated and may contain mistakes; the official description above is the record.