---
id: CVE-2026-82209
title: |-
  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., `Do…
summary: |-
  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., `Do…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N'
cwe:
  - CWE-201
  - CWE-501
vendor: haxx
product: curl
affected:
  - 'curl >= 7.46.0, < 8.22.0'
patched:
  - curl 8.22.0
published: '2026-09-06'
updated: '2026-09-15'
sourceUpdated: '2026-09-15T07:16:31.233'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82209'
references:
  - url: 'https://curl.se/docs/CVE-2026-82209.html'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://curl.se/docs/CVE-2026-82209.json'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3972385'
    label: 2499f714-1537-4658-8207-48ae4bb9eae9
  - url: 'https://hackerone.com/reports/3972385'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82209.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-82209'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2529207'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-82209'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82209'
  - url: 'https://access.redhat.com/errata/RHSA-2026:63161'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - score-dispute
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T18:47:09.259604Z'
epss: 0.00517
epssPercentile: 0.41459
ingestedAt: '2026-09-07T12:10:14.021Z'
scores:
  nvd: 8.2
  vendor: 3.1
---

## Overview

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`).

## Affected

- `curl >= 7.46.0, < 8.22.0`

## Remediation

Upgrade past the affected range:

- `curl 8.22.0`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat OpenShift Dev Spaces · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-82209.json)
- **RHSA-2026:63161** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63161)