CVE-2026-9546

Name
CVE-2026-9546
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.
NVD Severity
unknown
Other trackers
CVE, NVD, CERT, CVE Details, CIRCL, Arch Linux, Debian, Red Hat, Ubuntu, Gentoo, SUSE (Bugzilla), SUSE (CVE), Mageia
Mailing lists
oss-security, full-disclosure, bugtraq
Exploits
Exploit DB, Metasploit
Forges
GitHub (code, issues), Aports (code, issues)

References

Type URI
2499f714-1537-4658-8207-48ae4bb9eae9 https://curl.se/docs/CVE-2026-9546.html
2499f714-1537-4658-8207-48ae4bb9eae9 https://curl.se/docs/CVE-2026-9546.json
2499f714-1537-4658-8207-48ae4bb9eae9 https://hackerone.com/reports/3754343

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* curl >= 8.18.0 < 8.21.0

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
curl edge-main 8.21.0-r0 Achill Gilgenast <achill@achill.org> fixed
curl edge-main 8.20.0-r1 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl edge-main 8.20.0-r0 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl edge-main 8.19.0-r0 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl edge-main 8.18.0-r0 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl 3.24-main 8.21.0-r0 Achill Gilgenast <achill@achill.org> fixed
curl 3.24-main 8.20.0-r1 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl 3.23-main 8.20.0-r0 Achill Gilgenast <achill@achill.org> possibly vulnerable
curl 3.23-main 8.19.0-r0 Achill Gilgenast <achill@achill.org> possibly vulnerable