CVE-2026-19931

Negotiate ambient user conn reuse

CVE-2026-19931 is fixed in curl on 1 platform, first by DEBIAN-CVE-2026-19931, released September 19, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

9.8

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0075

55th percentile

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.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
curl · Debian 14	8.22.0~rc2-1	DEBIAN-CVE-2026-19931	Sep 19, 2026
curl · sles 15.6	8.22.0-150600.4.58.1	SUSE-SU-2026:5069-1	Nov 7, 2026
curl · sles 15.7	8.22.0-150700.7.33.1	SUSE-SU-2026:5068-1	Nov 7, 2026

Details

Published
September 6, 2026
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-19931

For tools and AI agents

This page as data: JSON · Markdown

Link to this page

If this page saved you time, a link to it in your ticket, advisory or write-up helps others find it.

HTML

<a href="https://patchblox.com/security/cve/CVE-2026-19931">CVE-2026-19931 on Patchblox Patch Radar</a>

Reusing the data? How to credit Patch Radar.

Is this on your machines?

Patchblox finds every install below the fixed version on Windows, macOS and Linux, and updates them through your release rings.

Get a demo

Patch Radar data is free to use with attribution. Terms and how to credit it.

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.