Improper Encoding or Escaping of Output vulnerability in elixir-tesla tesla allows multipart part header injection via unescaped Content-Disposition parameter values.
Tesla.Multipart.partheadersfordisposition/1 interpolates each disposition parameter as #{k}="#{v}" with no validation of CR (\r), LF (\n), or double-quote characters. The values come verbatim from the caller via Tesla.Multipart.addfield/4 (the name parameter), Tesla.Multipart.addfile/3, and Tesla.Multipart.addfilecontent/4 (both the filename parameter and other disposition opts). A " in the value closes the quoted parameter early; a \r\n ends the Content-Disposition header line and starts a new part header (such as a forged Content-Type), or, after a second \r\n, ends the entire part header block and prepends bytes to the part body. The default-filename path in addfile/3 derives the filename via Path.basename/1, which does not strip CR or LF, so any application forwarding a partially-attacker-controlled file path inherits the same issue.
This issue affects tesla: from 0.8.0 before 1.18.3.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48598.json",
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "6ebfdb9abe9c6f119408045b933d82462decd351"
},
{
"fixed": "bb1a2c3da2775924d96e3db8e315dcc4d5d2246e"
}
]
}
],
"cwe_ids": [
"CWE-116"
],
"cna_assigner": "EEF"
}