CVE-2026-19931Authentication bypass via connection reuse in libcurl
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.
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A critical flaw in libcurl allows the incorrect reuse of authenticated HTTP connections when using Negotiate authentication. This could allow an attacker or a different user to hijack an existing authenticated session, leading to unauthorized data access or impersonation.
Relevant roles
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCWE-488EPSS
Technical description
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.