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.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Curl
  • Curl
Haxx
  • Curl

Configuration 1 [-]

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

No data.

References
Link Providers
http://www.openwall.com/lists/oss-security/2026/03/11/3 cve-icon cve-icon
https://cert-portal.siemens.com/productcert/html/ssa-253495.html cve-icon
https://curl.se/docs/CVE-2026-3784.html cve-icon cve-icon cve-icon
https://curl.se/docs/CVE-2026-3784.json cve-icon cve-icon cve-icon
https://hackerone.com/reports/3584903 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-3784 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-3784 cve-icon
History

Tue, 02 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
References

Fri, 13 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 threat_severity

Moderate

Thu, 12 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Haxx
Haxx curl
CPEs cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
Vendors & Products Haxx
Haxx curl

Thu, 12 Mar 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Curl
Curl curl
Vendors & Products Curl
Curl curl

Wed, 11 Mar 2026 16:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-305
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 11 Mar 2026 11:30:00 +0000

Type Values Removed Values Added
References

Wed, 11 Mar 2026 10:30:00 +0000

Type Values Removed Values Added
Description 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.
Title wrong proxy connection reuse with credentials
References
cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-03-11T10:09:21.418Z

Updated: 2026-06-02T13:00:43.860Z

Reserved: 2026-03-08T05:09:52.279Z

Link: CVE-2026-3784

cve-icon Vulnrichment

Updated: 2026-03-11T10:16:32.844Z

cve-icon NVD

Status : Modified

Published: 2026-03-11T11:16:00.437

Modified: 2026-06-02T14:16:52.643

Link: CVE-2026-3784

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-11T10:09:21Z

Links: CVE-2026-3784 - Bugzilla