Vulnerability DatabaseCVE-2026-6276
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CVE-2026-6276
Published:May 13, 2026
Updated:May 16, 2026
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 Packages
https://github.com/curl/curl.git (GITHUB):
Affected version(s) >=curl-7_71_0 <curl-8_20_0
Fix Suggestion:
Update to version curl-8_20_0
Additional Notes
The description of this vulnerability differs from MITRE.
Related Resources (5)
https://curl.se/docs/CVE-2026-6276.json
http://www.openwall.com/lists/oss-security/2026/04/29/13
https://curl.se/docs/CVE-2026-6276.html
https://hackerone.com/reports/3671818
https://seclists.org/oss-sec/2026/q2/271
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CVSS v4
Base Score:
6.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
3.7
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Cleartext Transmission of Sensitive Information
CWE-319
EPSS
Base Score:
0.02