CVE-2026-9546

A vulnerability in libcurl caused the HTTP `Referer:` header to persist even when explicitly cleared. While the documentation states that passing NULL to `CURLOPT_REFERER` suppresses the header, the option failed to clear the internal state. As a result, the previous referrer string was erroneously reused and sent in subsequent requests, potentially leaking sensitive information to unintended servers.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://curl.se/docs/CVE-2026-9546.html	Patch Vendor Advisory
https://curl.se/docs/CVE-2026-9546.json	Third Party Advisory
https://hackerone.com/reports/3754343	Exploit Issue Tracking Third Party Advisory
https://hackerone.com/reports/3754343	Exploit Issue Tracking Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-07-03 07:16

Updated : 2026-09-15 07:16

NVD link : CVE-2026-9546

Mitre link : CVE-2026-9546

CVE.ORG link : CVE-2026-9546

JSON object : View

Products Affected

haxx

curl

CWE

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

NVD-CWE-noinfo

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