---
cve: "CVE-2026-59249"
severity: "MEDIUM"
cvss: 6.3
epss: "0.5%"
vendor: "elixir-mint"
kev: false
exploited: false
published: "2026-07-16 12:18:07"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-22T05:30:13+02:00"
---

# CVE-2026-59249

> 6.3 MEDIUM · 🧪 PoC

## Beschreibung

Inconsistent interpretation of HTTP requests (HTTP response smuggling) vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize a strict intermediary and the Mint client on the same pooled connection, enabling response-queue poisoning against subsequent requests that share the connection.

The Mint.HTTP1.decode_body/5 function in lib/mint/http1.ex parses the chunk-size line of a Transfer-Encoding: chunked response with Integer.parse(data, 16). RFC 7230 defines chunk-size = 1*HEXDIG and forbids any sign prefix, but Integer.parse/2 accepts an optional leading + or -. A chunk-size line of +5 is accepted as a five-byte chunk; lines of +0 and -0 are accepted as the terminating zero-length chunk and end the message body early.

An RFC-strict intermediary in the response path rejects these forms, so the intermediary and the Mint client disagree on where one response ends and the next begins. On a pooled keep-alive connection, an attacker-influenced origin can inject bytes that the client attributes to the next legitimate response on the same connection, poisoning the response queue and corrupting the responses returned to unrelated in-flight requests.

This issue affects mint: from 0.1.0 before 1.9.3.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- f0b72c0b2363c98d0a220019d108ac6141715428 (Commit)
- fc7d16538db7e40b56ed489f08683225cb0197fa (Commit)

## Referenzen

- <https://github.com/elixir-mint/mint/security/advisories/GHSA-x3x7-96vm-6h2w>
- <https://cna.erlef.org/cves/CVE-2026-59249.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-59249>
- <https://github.com/elixir-mint/mint/commit/fc7d16538db7e40b56ed489f08683225cb0197fa>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59249) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_