---
id: CVE-2026-3784
title: |-
  curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a
  server, even if the new request uses different credentials for the HTTP proxy.
  The proper behavior is to create or use a separate connection.
summary: |-
  curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a
  server, even if the new request uses different credentials for the HTTP proxy.
  The proper behavior is to create or use a separate connection.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-305
vendor: haxx
product: curl
affected:
  - 'curl >= 7.7, < 8.18.0'
patched:
  - curl 8.18.0
published: '2026-03-11'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T07:16:27.963'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-3784'
references:
  - url: 'https://curl.se/docs/CVE-2026-3784.html'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://curl.se/docs/CVE-2026-3784.json'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3584903'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'http://www.openwall.com/lists/oss-security/2026/03/11/3'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-253495.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3784.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-3784'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2446449'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-3784'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-3784'
  - url: 'https://access.redhat.com/errata/RHSA-2026:55450'
  - url: 'https://access.redhat.com/errata/RHSA-2026:6893'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-03-11T15:48:38.785522Z'
epss: 0.00412
epssPercentile: 0.35181
ingestedAt: '2026-09-15T07:33:29.263Z'
---

## Overview

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a
server, even if the new request uses different credentials for the HTTP proxy.
The proper behavior is to create or use a separate connection.

## Affected

- `curl >= 7.7, < 8.18.0`

## Remediation

Upgrade past the affected range:

- `curl 8.18.0`

## Vendor advisories

- **RHSA-2026:55450** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-08-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:55450)
- **RHSA-2026:6893** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:6893)
- **Red Hat VEX** · Moderate · affected: Confidential Compute Attestation, Logging Subsystem for Red Hat OpenShift, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · no fix planned: Confidential Compute Attestation, Logging Subsystem for Red Hat OpenShift, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, … · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3784.json)