When libpsl support is enabled, libcurl fails to enforce the Public Suffix List boundary check when processing a `Set-Cookie` header where the `Domain` attribute explicitly matches an origin host that is itself a public suffix (e.g., `Domain=co.uk` set by `co.uk`). Instead of coercing it into a strict host-only cookie, libcurl saves the cookie with wildcard domain scope (`.co.uk`). Consequently, the cookie is inappropriately included in subsequent outbound requests or HTTP redirects to arbitrary sibling subdomains under the same public suffix (e.g., `attacker.co.uk`).

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

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 yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Curl
  • Curl

No data.

No data.

References
Link Providers
https://curl.se/docs/CVE-2026-82209.html cve-icon cve-icon
https://curl.se/docs/CVE-2026-82209.json cve-icon cve-icon
https://hackerone.com/reports/3972385 cve-icon cve-icon cve-icon
History

Thu, 10 Sep 2026 05:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20

Tue, 08 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-201
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N'}

ssvc

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

Sun, 06 Sep 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Curl
Curl curl
Weaknesses CWE-20
Vendors & Products Curl
Curl curl

Sun, 06 Sep 2026 18:00:00 +0000

Type Values Removed Values Added
Description When libpsl support is enabled, libcurl fails to enforce the Public Suffix List boundary check when processing a `Set-Cookie` header where the `Domain` attribute explicitly matches an origin host that is itself a public suffix (e.g., `Domain=co.uk` set by `co.uk`). Instead of coercing it into a strict host-only cookie, libcurl saves the cookie with wildcard domain scope (`.co.uk`). Consequently, the cookie is inappropriately included in subsequent outbound requests or HTTP redirects to arbitrary sibling subdomains under the same public suffix (e.g., `attacker.co.uk`).
Title domain-scoped PSL domain cookie
References
cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-09-06T17:49:35.050Z

Updated: 2026-09-08T18:48:32.841Z

Reserved: 2026-08-28T08:25:48.340Z

Link: CVE-2026-82209

cve-icon Vulnrichment

Updated: 2026-09-08T18:42:52.227Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-09-06T18:17:22.847

Modified: 2026-09-08T19:20:00.313

Link: CVE-2026-82209

cve-icon Redhat

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