CVE-2026-9546

high

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://hackerone.com/reports/3754343

https://curl.se/docs/CVE-2026-9546.json

https://curl.se/docs/CVE-2026-9546.html

Details

Source: Mitre, NVD

Published: 2026-07-03

Updated: 2026-07-07

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:N/A:N

Severity: High

CVSS v3

Base Score: 7.5

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

Severity: High

EPSS

EPSS: 0.00206