# CVE-2026-6276

## Summary

- **CVE ID:** CVE-2026-6276
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-346
- **Published:** May 13, 2026
- **Last Modified:** Sep 17, 2026

## Description

Using libcurl, when a custom `Host:` header is first set for an HTTP request
and a second request is subsequently done using the same *easy handle* but
without the custom `Host:` header set, the second request would use stale
information and pass on cookies meant for the first host in the second
request. Leak them.

## Affected Products

- 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 (e15e51384a423be31318b3c9c7d612a1aae661fd)

## References

- [CNA](https://curl.se/docs/CVE-2026-6276.json)
- [CNA](https://curl.se/docs/CVE-2026-6276.html)
- [CNA](https://hackerone.com/reports/3671818)
- [CVE](http://www.openwall.com/lists/oss-security/2026/04/29/13)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.29%
- **EPSS Percentile:** 22.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._