CVE-2026-87861
Critical
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.
SeverityCritical
CVSS9.1
Exploit probability—
ProductCurl
PublishedOct 20, 2026
First seenOct 20, 2026
Weakness typeCWE-201CWE-201
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| curl curl | 8.22.0, 8.21.0 | — |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.