Bug 2535991

Summary:	CVE-2026-19931 curl: libcurl: Information disclosure via incorrect connection reuse with Negotiate authentication [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Srikanth Balasubramanian <sbalasub>
Component:	curl	Assignee:	Jan Macku <jamacku>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	jamacku, jmigacz, kdudka, lzaoral, msekleta, paul, vmihalko
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["c134493f-e35c-4e0f-a4dc-08ff2fab1752"]}
Fixed In Version:	curl-8.18.0-13.fc44	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-10-13 01:09:42 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2529199

Description Srikanth Balasubramanian 2026-09-17 13:10:55 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.

Comment 1 Fedora Update System 2026-09-30 08:46:44 UTC

FEDORA-2026-663a2d0ba4 (curl-8.21.0-6.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-663a2d0ba4

Comment 2 Fedora Update System 2026-10-01 02:19:28 UTC

FEDORA-2026-663a2d0ba4 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-663a2d0ba4`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-663a2d0ba4

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 3 Fedora Update System 2026-10-05 00:17:08 UTC

FEDORA-2026-663a2d0ba4 (curl-8.21.0-6.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 4 Fedora Update System 2026-10-09 07:44:53 UTC

FEDORA-2026-91d799048a (curl-8.18.0-13.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-91d799048a

Comment 5 Fedora Update System 2026-10-10 01:58:26 UTC

FEDORA-2026-91d799048a has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-91d799048a`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-91d799048a

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-10-13 01:09:42 UTC

FEDORA-2026-91d799048a (curl-8.18.0-13.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.