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CVE PROGRAM SOURCE RECORD2.1 Low

CVE-2026-48861

CRLF injection in HTTP/1 request line via unvalidated method in Mint

Description

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling. In lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\s, target, " HTTP/1.1\r\n"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection. Mint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions. This issue affects mint: from 0.1.0 before 1.9.0.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

elixir-mint mint

Default version status: unaffected

  • 0.1.0 to < 1.9.0affected
pkg:hex/mint

elixir-mint mint

Default version status: unaffected

  • 8db1acff30b6a9433762c18b1e1f891b8c1f74f7 to < fad091454cbb7449b19edb8e1fee12ca7cf28c3aaffected
pkg:github/elixir-mint/mint

References