CVE-2026-6276

Summary

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.

Impact & exploitability

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

Affected products we track (1)

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

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

Additional information

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