# CVE-2026-82209

## Summary

- **CVE ID:** CVE-2026-82209
- **Severity:** HIGH
- **CVSS Score:** 8.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N)
- **CWE:** CWE-201
- **Published:** Sep 6, 2026
- **Last Modified:** Sep 16, 2026

## 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`).

## Affected Products

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

## References

- [CNA](https://curl.se/docs/CVE-2026-82209.json)
- [CNA](https://curl.se/docs/CVE-2026-82209.html)
- [CNA](https://hackerone.com/reports/3972385)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.54%
- **EPSS Percentile:** 44.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._