# CVE-2026-9546

## Summary

- **CVE ID:** CVE-2026-9546
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
- **CWE:** CWE-200
- **Published:** Jul 3, 2026
- **Last Modified:** Sep 17, 2026

## 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.

## Affected Products

- curl — curl (8.20.0)
- curl — curl (8.19.0)
- curl — curl (8.18.0)
- curl — curl (2cb868242dc2ac9cd52ee64987ef51d5964a56f9)

## References

- [CNA](https://curl.se/docs/CVE-2026-9546.json)
- [CNA](https://curl.se/docs/CVE-2026-9546.html)
- [CNA](https://hackerone.com/reports/3754343)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.49%
- **EPSS Percentile:** 41.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._