CVE-2026-53423: Membrane mp4 plugin Membrane_mp4_plugin Has An Unauthenticated Denial-of-service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-43hj-fxwj-49qw",
  "modified" : "2026-08-18T20:16:29Z",
  "published" : "2026-08-18T20:16:29Z",
  "aliases" : [ "CVE-2026-53423" ],
  "summary" : "membrane_mp4_plugin has an unauthenticated denial-of-service via BEAM atom table exhaustion",
  "details" : "### Summary\n\n`membrane_mp4_plugin` interns every 4-byte MP4 box name as a BEAM atom while parsing container headers, with no validation against an allow-list. Any code path that calls `Membrane.MP4.Container.parse/1` (or the bang variant) on attacker-controlled MP4 bytes can be made to exhaust the BEAM atom table, which is uncapped at the source but bounded by the runtime ceiling (around 1,048,576 atoms) and never garbage-collected. Once the ceiling is hit, the entire BEAM node aborts.\n\n### Details\n\nThe MP4 container parser walks the input stream box-by-box. For each box, `Membrane.MP4.Container.Header.parse/1` in `lib/membrane_mp4/container/header.ex` extracts the 4-byte name field and delegates to the private helper `parse_box_name/1`, which trims trailing spaces and passes the bytes through `String.to_atom/1`. Because `String.to_atom/1` creates a new atom unconditionally, every distinct attacker-chosen 4-byte sequence becomes a permanent allocation in the global atom table. Atoms are not subject to garbage collection, so unique names accumulate for the lifetime of the node.\n\nThe fix replaces the unsafe interning with `String.to_existing_atom/1` and treats unknown names as the `:unknown` atom downstream (with related plumbing in `parse_helper.ex`, `serialize_helper.ex`, and the ISOM/CMAF demuxer engines so the new error variant flows through cleanly).\n\n### PoC\n\n1. Generate an MP4-shaped payload of roughly 1.1 million minimal box headers, each 8 bytes long (4-byte size of 8, followed by a unique 4-byte ASCII name produced by enumerating combinations in the printable range).\n2. Concatenate them into a single binary (~8 MB total).\n3. Call `Membrane.MP4.Container.parse!/1` on the binary inside any process running under the target BEAM node.\n4. The node aborts once the atom table ceiling is reached.\n\n### Impact\n\nAn attacker who can get a single crafted MP4 file in front of any system that demuxes user-supplied media with `membrane_mp4_plugin` can crash the entire BEAM node hosting that pipeline, taking down every Erlang/Elixir application sharing the runtime. No authentication, network position, or user interaction is required beyond delivering the file to whatever processing path eventually calls the parser.\n\n### References\n\n* Introduction commit: https://github.com/membraneframework/membrane_mp4_plugin/commit/ae4bf04c393aa1562f3df3d33e20bc5cb8130de2\n* Patch commit: https://github.com/membraneframework/membrane_mp4_plugin/commit/56373d1ddc86968e55fbde795c14eeba24357b57",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Hex",
      "name" : "membrane_mp4_plugin"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.36.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/membraneframework/membrane_mp4_plugin/security/advisories/GHSA-43hj-fxwj-49qw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53423"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/membraneframework/membrane_mp4_plugin/commit/56373d1ddc86968e55fbde795c14eeba24357b57"
  }, {
    "type" : "WEB",
    "url" : "https://cna.erlef.org/cves/CVE-2026-53423.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/membraneframework/membrane_mp4_plugin"
  }, {
    "type" : "WEB",
    "url" : "https://osv.dev/vulnerability/EEF-CVE-2026-53423"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-18T20:16:29Z",
    "nvd_published_at" : "2026-06-11T12:16:31Z"
  }
}