CVE-2026-9546EPSS p49.6%
CVE-2026-9546CVE-2026-9546
haxx / curl
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.
Scoring
| CVSS | 7.5 () |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| EPSS | 0.65% probability of exploitation · percentile 49.6% · 2026-10-06T12:00:23Z |
| Last modified | 2026-09-15 |