When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation poc

Automatable no

Technical Impact total

Affected Vendors & Products

Vendors Products
Curl
  • Curl

No data.

No data.

References
Link Providers
https://curl.se/docs/CVE-2026-8927.html cve-icon cve-icon
https://curl.se/docs/CVE-2026-8927.json cve-icon cve-icon
https://hackerone.com/reports/3744543 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-8927 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-8927 cve-icon
History

Tue, 07 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-201
References
Metrics threat_severity

None

 threat_severity

Important

Mon, 06 Jul 2026 22:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Mon, 06 Jul 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Sun, 05 Jul 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Sun, 05 Jul 2026 01:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-306

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

Type Values Removed Values Added
Weaknesses CWE-200
CWE-306

Fri, 03 Jul 2026 21:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Fri, 03 Jul 2026 11:00:00 +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

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

Type Values Removed Values Added
Description When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.
Title env-set cross-proxy Digest auth state leak
References
cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-07-03T06:16:06.376Z

Updated: 2026-07-06T17:01:06.213Z

Reserved: 2026-05-19T08:12:08.842Z

Link: CVE-2026-8927

cve-icon Vulnrichment

Updated: 2026-07-06T17:01:00.942Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-03T06:16:06Z

Links: CVE-2026-8927 - Bugzilla