CVE-2026-7168: Haxx Curl

Medium severity, CVSS 5.3. EPSS: 0.6% chance of exploitation in the next 30 days.

Successfully using libcurl to do a transfer over a specific HTTP proxy (`proxyA`) with **Digest** authentication and then changing the proxy host to a second one (`proxyB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Proxy-Authorization:` header field meant for `proxyA`, to `proxyB`.

Affected products

• Haxx Curl: from 7.12.0, before 8.20.0 (fixed in 8.20.0)

Published 2026-05-13. Last modified 2026-09-15.