CVE-2026-82209 — domain-scoped PSL domain cookie

Description (CNA)

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 (CNA)

Vendor / product	Versions
curl / curl	affected 7.46.0 before 8.14.2; affected 8.15.0 before 8.16.1; affected 8.17.0 before 8.20.1; affected 8.21.0 before 8.22.0
curl / curl	affected e77b5b7453c1e8ccd7ec0816890d98e2f392e465 before 95c1e8915dce64606bd753fd47fc0bd236e31cd6
curl / curl	affected 8.21.0; affected 8.20.0; affected 8.19.0; affected 8.18.0; affected 8.17.0; affected 8.16.0; affected 8.15.0; affected 8.14.1; affected 8.14.0; affected 8.13.0; affected 8.12.1; affected 8.12.0; affected 8.11.1; affected 8.11.0; affected 8.10.1; affected 8.10.0; affected 8.9.1; affected 8.9.0; affected 8.8.0; affected 8.7.1; affected 8.7.0; affected 8.6.0; affected 8.5.0; affected 8.4.0; affected 8.3.0; affected 8.2.1; affected 8.2.0; affected 8.1.2; affected 8.1.1; affected 8.1.0; affected 8.0.1; affected 8.0.0; affected 7.88.1; affected 7.88.0; affected 7.87.0; affected 7.86.0; affected 7.85.0; affected 7.84.0; affected 7.83.1; affected 7.83.0; affected 7.82.0; affected 7.81.0; affected 7.80.0; affected 7.79.1; affected 7.79.0; affected 7.78.0; affected 7.77.0; affected 7.76.1; affected 7.76.0; affected 7.75.0; affected 7.74.0; affected 7.73.0; affected 7.72.0; affected 7.71.1; affected 7.71.0; affected 7.70.0; affected 7.69.1; affected 7.69.0; affected 7.68.0; affected 7.67.0; affected 7.66.0; affected 7.65.3; affected 7.65.2; affected 7.65.1; affected 7.65.0; affected 7.64.1; affected 7.64.0; affected 7.63.0; affected 7.62.0; affected 7.61.1; affected 7.61.0; affected 7.60.0; affected 7.59.0; affected 7.58.0; affected 7.57.0; affected 7.56.1; affected 7.56.0; affected 7.55.1; affected 7.55.0; affected 7.54.1; affected 7.54.0; affected 7.53.1; affected 7.53.0; affected 7.52.1; affected 7.52.0; affected 7.51.0; affected 7.50.3; affected 7.50.2; affected 7.50.1; affected 7.50.0; affected 7.49.1; affected 7.49.0; affected 7.48.0; affected 7.47.1; affected 7.47.0; affected 7.46.0

CWE

CWE-201

References

ADP enrichment

CISA-ADP

No English description supplied.

https://hackerone.com/reports/3972385