Information disclosure in cURL - CVE-2026-9546
Published: June 24, 2026
Vulnerability identifier: #VU135088
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-9546
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: curl.haxx.se
Affected software:
cURL
cURL
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to exposure of sensitive information in the libcurl HTTP Referer header handling when processing subsequent HTTP requests after CURLOPT_REFERER is cleared with NULL. A remote attacker can receive a subsequent request that erroneously includes a previously configured Referer header to disclose sensitive information.
This issue affects libcurl and does not affect the curl command line tool.
How to mitigate CVE-2026-9546
Install security update from vendor's website.