CVE-2026-86413
Description
A flaw was found in curl. When curl is configured to follow HTTP redirects while performing Negotiate authentication using system-provided Kerberos credentials, it may forward authentication details to an unrelated destination. A malicious server can exploit this flaw by redirecting the client to a target URL containing embedded user credentials, resulting in information disclosure of sensitive authentication data.
Statement
Red Hat rates this vulnerability as Low impact because successful credential exposure requires an uncommon combination of conditions: an HTTP request using Negotiate authentication with ambient Kerberos credentials must be configured to follow redirects to a secondary URL with embedded credentials. Furthermore, core Red Hat Enterprise Linux distributions ship curl versions outside the affected upstream release window. In typical enterprise environments, Kerberos-authenticated transfers rarely follow automated redirects across disparate origins, significantly limiting exposure in practice.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Acknowledgements
Red Hat would like to thank Stanislav Fort (Aisle Research) for reporting this issue.
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