CVE-2026-6276

high

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.

References

https://hackerone.com/reports/3671818

https://curl.se/docs/CVE-2026-6276.json

https://curl.se/docs/CVE-2026-6276.html

http://www.openwall.com/lists/oss-security/2026/04/29/13

Details

Source: Mitre, NVD

Published: 2026-05-13

Updated: 2026-05-14

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

EPSS

EPSS: 0.00008