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CRITICAL · 9.1

CVE-2026-87861

When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's int...

Vulnerability Description

When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused.

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-2026-87861?

CVE-2026-87861 is a vulnerability with a CVSS score of 9.1 (CRITICAL). When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's int...

How severe is CVE-2026-87861?

CVE-2026-87861 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-2026-87861?

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