All vulnerabilities

Servers and applications

CVE-2026-9546

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…

Severity
High 7.5
Published
3 Jul 2026
Last changed
15 Sept 2026
Added to UpHeron
21 Oct 2026
Fixed in
8.21.0
Sources
NVD

Affected software

SoftwareAffected versions
curlServers and applications · cpe:a:haxx:curl
  • From 8.18.0 before 8.21.0

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2026-9546
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2026-9546