CVE-2026-19931
Critical
Description
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.
SeverityCritical
CVSS9.8
Exploit probability—
ProductHaxx Curl
PublishedSep 6, 2026
First seenSep 6, 2026
Weakness typeCWE-488CWE-488
How to fix
Update
- haxx curl8.22.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| haxx curl | 7.64.1 ≤ v < 8.22.0 | 8.22.0 |
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.