CVE-2026-1965
curl: curl: Authentication bypass due to incorrect connection reuse with Negotiate authentication
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · March 11, 2026
Updated · November 2, 2026
Description
A flaw was found in curl. When an application uses libcurl to make multiple Negotiate-authenticated HTTP or HTTPS requests to the same server with different credentials, libcurl may incorrectly reuse an existing connection. This logical error can cause a subsequent request to be sent using the authentication of a previous user, leading to an authentication bypass.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
CVSS / CWE
CVSS 3.1 · 6.8CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CWE-303 · Incorrect Implementation of Authentication Algorithm