CVE-2026-9546EPSS p33.1%
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 | 0.40% probability of exploitation · percentile 33.1% · 2026-08-17T12:03:47Z |
| Last modified | 2026-07-07 |