Vulnerability Report

CVE-2026-9546

Title: Referer Header Persistence

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-9546.

CWE Category NVD-CWE-noinfo

Published Date Jul 03, 2026

Modified Date Jul 07, 2026

Exploit Status Not Found

Score 7.5 CVSS v

Exploit Probability (EPSS)

0.65%

Vulnerability Summary

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.

Impacted Vendors

haxx 1

Reference Links

https://curl.se/docs/CVE-2026-9546.html https://curl.se/docs/CVE-2026-9546.json https://hackerone.com/reports/3754343

CVSS v3.1

Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-9546 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

July 07, 2026 MODIFIED

Vulnerability data updated via NVD.

July 06, 2026 MODIFIED

Vulnerability data updated via NVD.

July 03, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


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

Affected Stack

No specific products linked.