# CVE-2026-84384: libheif: brotli/zlib decompression paths lack output-size limits, allowing decompression-bomb OOM/DoS

> Crafted HEIF or AVIF files can cause unbounded memory consumption in libheif, leading to application crashes via decompression bombs.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** BELL-CVE-2026-84384, DEBIAN-CVE-2026-84384, ECHO-0bbf-2ab0-3791, GHSA-24wx-9w62-c96w, MINI-65hh-jw4r-jqr9, ROOT-OS-DEBIAN-12-CVE-2026-84384, UBUNTU-CVE-2026-84384

## What is CVE-2026-84384?

CVE-2026-84384 is a high-severity denial of service vulnerability in strukturag libheif, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-409 (Improper Handling of Highly Compressed Data (Data Amplification))

## Which versions are affected by CVE-2026-84384?


## How do I fix CVE-2026-84384?

Upgrade to a fixed version.

## Is CVE-2026-84384 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-84384 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-84384 and fix it if it is affected.

What it is: CVE-2026-84384 is a high-severity denial of service vulnerability in strukturag libheif, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-84384 exists.

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-2026-84384/ (Markdown: https://insights.sbomify.com/CVE-2026-84384/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84384
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84384
- OSV: https://osv.dev/vulnerability/CVE-2026-84384

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-84384/
Summaries are generated and may contain mistakes; the official description above is the record.