Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation poc

Automatable yes

Technical Impact total

Affected Vendors & Products

Vendors Products
Curl
  • Curl
Redhat
  • Hummingbird

No data.

Package CPE Advisory Released Date
Red Hat Hardened Images
rust-main-1.96.1-1.hum1 cpe:/a:redhat:hummingbird:1 RHSA-2026:34975 2026-07-02T00:00:00Z
References
Link Providers
https://curl.se/docs/CVE-2026-11856.html cve-icon cve-icon
https://curl.se/docs/CVE-2026-11856.json cve-icon cve-icon
https://hackerone.com/reports/3793260 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-11856 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-11856 cve-icon
History

Thu, 09 Jul 2026 00:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Thu, 09 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-201
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

 threat_severity

Moderate

Wed, 08 Jul 2026 11:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Wed, 08 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Mon, 06 Jul 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Mon, 06 Jul 2026 13:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Sun, 05 Jul 2026 05:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Sat, 04 Jul 2026 17:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-798

Sat, 04 Jul 2026 09:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-798

Sat, 04 Jul 2026 05:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-639

Fri, 03 Jul 2026 10:45:00 +0000

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

Fri, 03 Jul 2026 10:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-639

Fri, 03 Jul 2026 06:45:00 +0000

Type Values Removed Values Added
Description Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.
Title cross-origin Digest auth state leak
References
cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-07-03T06:13:31.661Z

Updated: 2026-07-06T18:23:52.111Z

Reserved: 2026-06-10T08:59:16.646Z

Link: CVE-2026-11856

cve-icon Vulnrichment

Updated: 2026-07-06T18:23:29.315Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-03T06:13:31Z

Links: CVE-2026-11856 - Bugzilla