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`).
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade curl | Sep 7, 2026 | Sep 6, 2026 |
| Ibm Aix | — | Apply the fix or workaround for curl_advisory13 | Oct 15, 2026 | Oct 14, 2026 |
| Redhat_linux | — | No solution exists | Sep 21, 2026 | Sep 6, 2026 |
| Ubuntu | — | Upgrade libcurl4-openssl-dev (Ubuntu Pro)Upgrade libcurl3t64-gnutlsUpgrade libcurl4t64Upgrade libcurl3 (Ubuntu Pro)Upgrade libcurl4-gnutls-devUpgrade curlUpgrade libcurl4-nss-dev (Ubuntu Pro)Upgrade libcurl4 (Ubuntu Pro)Upgrade libcurl4-openssl-devUpgrade libcurl3-gnutls (Ubuntu Pro)Upgrade libcurl4Upgrade libcurl4-gnutls-dev (Ubuntu Pro)Upgrade libcurl4-nss-devUpgrade libcurl3-nssUpgrade libcurl3-nss (Ubuntu Pro)Upgrade libcurl3-gnutlsUpgrade curl (Ubuntu Pro) | Sep 27, 2026 | Sep 24, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Sep 24, 2026 | Sep 6, 2026 |
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