Description
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.
References
https://curl.se/docs/CVE-2026-9546.html
https://curl.se/docs/CVE-2026-9546.json
https://hackerone.com/reports/3754343
https://hackerone.com/reports/3754343
Weaknesses
2499f714-1537-4658-8207-48ae4bb9eae9
CVSS impact metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5 · High
Information
Source identifier
2499f714-1537-4658-8207-48ae4bb9eae9
Vulnerability status
Modified
Published
2026-07-03T07:16:25.893Z
3 months agoLast modified
2026-09-15T07:16:35.130Z
3 weeks ago