CVE-2026-48596: Tesla Tesla Has CRLF Injection Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q7jx-v53g-848w",
  "modified" : "2026-07-10T00:03:12Z",
  "published" : "2026-07-10T00:03:12Z",
  "aliases" : [ "CVE-2026-48596" ],
  "summary" : "Tesla has CRLF injection in request `Content-Type` header via `add_content_type_param`",
  "details" : "### Summary\n\n`Tesla.Multipart.add_content_type_param/2` appends caller-supplied strings to the multipart `Content-Type` header with no validation. A param value containing `\\r\\n` splits the header line, allowing an attacker who controls any content-type parameter (charset, boundary parameter, etc.) to inject arbitrary headers into the outbound HTTP request.\n\n### Details\n\n`add_content_type_param/2` in `lib/tesla/multipart.ex` stores the supplied string directly in `multipart.content_type_params` without any CR/LF check. `headers/1` then joins all params with `\"; \"` and appends the result verbatim to the `Content-Type` header value. Because HTTP headers are delimited by `\\r\\n`, a param containing that sequence breaks out of the header field and introduces new header lines before the adapter writes the request to the socket.\n\nThe precondition is that untrusted input reaches `add_content_type_param/2`, which is the normal pattern for applications that accept user-supplied charset values, file type parameters, or any other content-type extension fields.\n\n### PoC\n\n1. Call `Tesla.Multipart.add_content_type_param/2` with a value containing `\\r\\nX-Injected: pwned`.\n2. Pass the resulting `Multipart` struct as the request body via any Tesla adapter.\n3. The raw request on the wire contains `X-Injected: pwned` as a standalone header line.\n\n### Impact\n\nLow severity (CVSS v4.0: 2.1). Any application using `tesla` 0.8.0 through 1.18.2 that passes untrusted input into `Tesla.Multipart.add_content_type_param/2` is affected. Consequences range from forging arbitrary outbound request headers to potential request smuggling against the upstream server. Fixed in tesla 1.18.3.\n\n### Workarounds\n\nValidate content-type parameter strings before passing them to `Tesla.Multipart.add_content_type_param/2`, rejecting any value that contains `\\r` or `\\n`.\n\n### Reesources\n\n* Introduction commit: https://github.com/elixir-tesla/tesla/commit/6ebfdb9abe9c6f119408045b933d82462decd351\n* Patch commit: https://github.com/elixir-tesla/tesla/commit/23601edac5d22ba9407b427967b5bdbda201aec2",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Hex",
      "name" : "tesla"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.8.0"
      }, {
        "fixed" : "1.18.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/elixir-tesla/tesla/security/advisories/GHSA-q7jx-v53g-848w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-48596"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/elixir-tesla/tesla/commit/23601edac5d22ba9407b427967b5bdbda201aec2"
  }, {
    "type" : "WEB",
    "url" : "https://cna.erlef.org/cves/CVE-2026-48596.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/elixir-tesla/tesla"
  }, {
    "type" : "WEB",
    "url" : "https://osv.dev/vulnerability/EEF-CVE-2026-48596"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-113", "CWE-93" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-10T00:03:12Z",
    "nvd_published_at" : "2026-06-02T20:16:38Z"
  }
}