CVE-2026-6276

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.

CVSS Vector

References

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