CVE-2026-86413 — CRITICAL (9.1)

Vulnerability Description

When using an *ambient user* in a first transfer doing Negotiate authentication and asked to follow redirects, curl could pass on its credential details to an unrelated second origin when asked to redirect there.

CVSS Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-201

References

FAQ

What is CVE-2026-86413?

CVE-2026-86413 is a vulnerability with a CVSS score of 9.1 (CRITICAL). When using an *ambient user* in a first transfer doing Negotiate authentication and asked to follow redirects, curl could pass on its credential details to an unrelated second origin when asked to red...

How severe is CVE-2026-86413?

CVE-2026-86413 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-86413?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.