CVE-2026-6276
Last modified
CVE-2026-6276 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 0.29% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Haxx | Curl | >= 7.71.0, < 8.20.0 |
References
- https://curl.se/docs/CVE-2026-6276.htmlPatch, Vendor Advisory
- https://hackerone.com/reports/3671818Exploit, Issue Tracking, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/29/13Mailing List, Third Party Advisory
- https://hackerone.com/reports/3671818Exploit, Issue Tracking, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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