CVE-2026-48594: Tesla Tesla Has Decompression Bomb On Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mc85-72gr-vm9f",
  "modified" : "2026-07-10T00:03:23Z",
  "published" : "2026-07-10T00:03:23Z",
  "aliases" : [ "CVE-2026-48594" ],
  "summary" : "Tesla has decompression bomb on response body",
  "details" : "### Summary\n\nAny Tesla client pipeline that includes `Tesla.Middleware.DecompressResponse` or `Tesla.Middleware.Compression` eagerly decompresses HTTP response bodies with no size limit. A server under attacker control (or reached via a redirect) can return a tiny gzip-encoded payload that expands into gigabytes of BEAM heap, crashing or freezing the calling process. Stacking multiple `content-encoding` tokens multiplies the amplification exponentially.\n\n### Details\n\n`decompress_body/2` in `lib/tesla/middleware/compression.ex` passes the full response body to `:zlib.gunzip/1` or `:zlib.unzip/1` with no cap on output size. The list of codec tokens comes from splitting the `content-encoding` header on commas, and `decompress_body/2` recurses once per token. A response advertising `content-encoding: gzip, gzip, gzip, gzip` triggers four recursive decompression passes. Each gzip layer can expand its input roughly 1000x, so a 284-byte wire payload with four layers inflates to approximately 1 GB at the innermost pass, all materialised as a single binary in the caller's heap.\n\n### PoC\n\n1. Serve an HTTP response with `content-encoding: gzip, gzip, gzip, gzip` where the body is a 1 GB block of zeros compressed through four successive gzip passes.\n2. Send that response to a Tesla client whose pipeline includes `Tesla.Middleware.DecompressResponse`.\n3. `decompress_body/2` recurses four times without any size check, materialising ~1 GB in the calling process's heap.\n4. Repeated or sufficiently large requests exhaust available memory and crash or freeze the node.\n\n### Impact\n\nHigh severity (CVSS v4.0: 8.2). Any application using `tesla` 0.6.0 through 1.18.2 with `Tesla.Middleware.DecompressResponse` or `Tesla.Middleware.Compression` in its pipeline is vulnerable. The attacker only needs to control a server the client contacts, including via redirects. Fixed in tesla 1.18.3.\n\n### Configurations\n\nThe application must include `Tesla.Middleware.DecompressResponse` or `Tesla.Middleware.Compression` in its Tesla middleware pipeline.\n\n### Resources\n\n* Introduction commit: https://github.com/elixir-tesla/tesla/commit/5bd90bb5cf0d15e375edc2a66fa322292940fce2\n* Patch commit: https://github.com/elixir-tesla/tesla/commit/340f75b5d191dc747ef7ac6365bd002d1cd55a9d",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/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" : "tesla"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.6.0"
      }, {
        "fixed" : "1.18.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/elixir-tesla/tesla/security/advisories/GHSA-mc85-72gr-vm9f"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-48594"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/elixir-tesla/tesla/commit/340f75b5d191dc747ef7ac6365bd002d1cd55a9d"
  }, {
    "type" : "WEB",
    "url" : "https://cna.erlef.org/cves/CVE-2026-48594.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/elixir-tesla/tesla"
  }, {
    "type" : "WEB",
    "url" : "https://osv.dev/vulnerability/EEF-CVE-2026-48594"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-409" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-10T00:03:23Z",
    "nvd_published_at" : "2026-06-02T20:16:38Z"
  }
}