# CVE-2026-48861: Elixir Mint CRLF injection in HTTP/1 request line

Source: https://junglewise.ai/threats/cve-2026-48861-elixir-mint-crlf-injection-in-http-1-request-line  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-02. Updated: 2026-07-10  
License: CC BY 4.0 with a link back

CVE-2026-48861 · Severity: low · CVSS 2.1 · Published 2026-06-02

Mint is a low-level HTTP client for the Elixir programming language. A vulnerability in how it handles request methods allows an attacker to inject malicious commands into a web request if the application uses untrusted input to define the HTTP method. This could allow an attacker to bypass security controls, forge headers, or perform unauthorized actions on internal servers.

Technologies: [Elixir-Mint Mint](https://junglewise.ai/threats/technologies/mint). Vendors: [Elixir-Mint](https://junglewise.ai/threats/vendors/elixir-mint).

## Quick answers

**Is CVE-2026-48861 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48861 being exploited in the wild.

**How severe is CVE-2026-48861?** Low severity, with a CVSS score of 2.1, published 2 June 2026.

**Which products and versions are affected?** Elixir-Mint Mint < 1.9.0, 0.1.0 to 1.8.0.

**Is there a fix for CVE-2026-48861?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-48861 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-48861?** Check whether you run Elixir-Mint Mint at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in Mint's HTTP/1 request encoder, specifically within the `encode_request_line/2` function in `lib/mint/http1/request.ex`. The library writes the user-supplied `method` and `target` strings directly to the socket without validating them for Carriage Return or Line Feed (CRLF) characters. If an application passes attacker-controlled input as the HTTP method, the attacker can terminate the request line early and inject arbitrary headers or even a second, 'smuggled' HTTP request. While version 1.7.0 introduced validation for the `target` field, the `method` field remained unvalidated until version 1.9.0. This can lead to request smuggling and cache poisoning when Mint is used in proxy or gateway applications.

## Affected products

- elixir-mint mint < 1.9.0

## Identifiers

- CVE-2026-48861
- GHSA-2pg6-44cx-c49v

## Timeline

- 2026-06-02: disclosed: NVD publication date
- 2026-07-09: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/PJUllrich](https://api.github.com/users/PJUllrich)
- [https://github.com/PJUllrich](https://github.com/PJUllrich)
- [https://api.github.com/users/PJUllrich/gists%7B/gist_id%7D](https://api.github.com/users/PJUllrich/gists%7B/gist_id%7D)
- [https://api.github.com/users/PJUllrich/repos](https://api.github.com/users/PJUllrich/repos)
- [https://avatars.githubusercontent.com/u/10426523?v=4](https://avatars.githubusercontent.com/u/10426523?v=4)
- [https://api.github.com/users/PJUllrich/events%7B/privacy%7D](https://api.github.com/users/PJUllrich/events%7B/privacy%7D)

## Related threats

- [Mint HTTP request/response smuggling in transfer encoding parsing](https://junglewise.ai/threats/cve-2026-94194-inconsistent-interpretation-of-http-requests-http-request)
- [Elixir Mint HTTP/2 frame buffer exhaustion](https://junglewise.ai/threats/cve-2026-92103-allocation-of-resources-without-limits-or-throttling)
- [Mint HTTP/2 header list memory exhaustion denial of service](https://junglewise.ai/threats/cve-2026-91043-allocation-of-resources-without-limits-or-throttling)
- [Elixir Mint HTTP request smuggling in chunked transfer encoding](https://junglewise.ai/threats/cve-2026-82672-inconsistent-interpretation-of-http-requests-http-request)
- [elixir-mint HTTP/1 parser algorithmic complexity denial of service](https://junglewise.ai/threats/cve-2026-82729-elixir-mint-http-1-parser-algorithmic-complexity-denial-of)