Vulnerability · Published Jun 2, 2026 · Assigned by EEF
CVE-2026-48861CRLF injection in HTTP/1 request line via unvalidated method in Mint
Low 2.1
In plain English
A low-severity security flaw in mint from elixir-mint. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).
Official 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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| elixir-mint | mint | 0.1.0 – before 1.9.0 |
| elixir-mint | mint | 8db1acff30b6a9433762c18b1e1f891b8c1f74f7 – before fad091454cbb7449b19edb8e1fee12ca7cf28c3a |
Weakness: CWE-93 · Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N