# CVE-2026-53423: Unauthenticated denial-of-service via BEAM atom table exhaustion in membrane_mp4_plugin

> Unauthenticated attackers can crash the BEAM node by exhausting the atom table via crafted MP4 files in the membrane_mp4_plugin library.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jun 2026
- **Updated:** 12 Jun 2026
- **Also known as:** EEF-CVE-2026-53423, GHSA-43hj-fxwj-49qw

## What is CVE-2026-53423?

CVE-2026-53423 is a medium-severity denial of service vulnerability in membraneframework membrane_mp4_plugin, published on 11 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Allocation of Resources Without Limits or Throttling vulnerability in membraneframework membrane_mp4_plugin allows unauthenticated denial-of-service via BEAM atom table exhaustion.

The MP4 box header parser converts each 4-byte box name to an atom using String.to_atom/1 without validation. 'Elixir.Membrane.MP4.Container.Header':parse_box_name/1 in lib/membrane_mp4/container/header.ex interns every box name encountered while 'Elixir.Membrane.MP4.Container.Header':parse/1 walks the input. BEAM atoms are never garbage-collected, so each unique attacker-controlled 4-byte name is a permanent allocation. A crafted MP4 of approximately 8 MB containing roughly 1.1 million boxes with distinct non-standard names exhausts the atom table (default ceiling around 1,048,576 atoms), aborting the entire BEAM node and taking down all applications running on it.

This issue affects membrane_mp4_plugin from 0.3.0 before 0.36.7.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-53423?

3 open source packages ship an affected version, including membrane_mp4_plugin.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `membrane_mp4_plugin` | Hex | All versions | 0.36.7 |
| `membrane_mp4_plugin` | Hex | All versions | 0.36.7 |
| `membrane_mp4_plugin` | Hex | From 0.3.0 | 0.36.7 |

## How do I fix CVE-2026-53423?

Upgrade membrane_mp4_plugin to 0.36.7 or later.

## Is CVE-2026-53423 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53423 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53423 and fix it if it is affected.

What it is: CVE-2026-53423 is a medium-severity denial of service vulnerability in membraneframework membrane_mp4_plugin, published on 11 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53423 exists.

Affected packages and fixed versions:
- membrane_mp4_plugin (Hex): affected all versions; fixed in 0.36.7
- membrane_mp4_plugin (Hex): affected all versions; fixed in 0.36.7
- membrane_mp4_plugin (Hex): affected from 0.3.0; fixed in 0.36.7

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-2026-53423/ (Markdown: https://insights.sbomify.com/CVE-2026-53423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53423
- OSV: https://osv.dev/vulnerability/CVE-2026-53423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53423/
Summaries are generated and may contain mistakes; the official description above is the record.