---
id: CVE-2026-82729
title: >-
  Inefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a
  remote HTTP server to exhaust CPU on the client host and cause a denial of
  service.


  parse_hex_prefix/2 in lib/mint/http1/parse.ex folds each hex digit of a ch…
summary: >-
  Inefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a
  remote HTTP server to exhaust CPU on the client host and cause a denial of
  service.


  parse_hex_prefix/2 in lib/mint/http1/parse.ex folds each hex digit of a ch…
severity: none
cwe:
  - CWE-407
published: '2026-09-04'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T14:16:14.947'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82729'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-82729.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/elixir-mint/mint/commit/bd2a4e7513594997c140cfef9fe0e968712fb588
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-82729'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/elixir-mint/mint/security/advisories/GHSA-7p8w-j234-7qc8
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00524
epssPercentile: 0.41991
ingestedAt: '2026-09-08T15:33:26.961Z'
---

## Overview

Inefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a remote HTTP server to exhaust CPU on the client host and cause a denial of service.

parse_hex_prefix/2 in lib/mint/http1/parse.ex folds each hex digit of a chunked response's chunk-size field into an arbitrary-precision accumulator with acc * 16 + digit and imposes no limit on the digit count. Because the accumulator grows without bound, the multiplication is not constant time and one pass over N digits costs O(N squared). handle_data/2 prepends conn.buffer and re-parses from the start on every socket message, so a server that dribbles the digits out in small packets makes the client pay that cost repeatedly. A run of roughly 512,000 hex digits costs over ten seconds of CPU in a single pass, measured on stock defaults. The parser reaches this state after a valid status line and a complete, valid header section, so an intermediary inspecting only headers sees an ordinary 200 response.

This issue affects mint: from 1.9.3 before 1.10.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.