Bug 2524358

Summary: CVE-2026-19538 nsd: nsd: Access control bypass via repeated queries on proxy protocol port [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Vladimir Vasilev <vvasilev>
Component: nsdAssignee: Paul Wouters <paul.wouters>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: epel10CC: drjohnson1, me, paul.wouters
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["8fb8b524-a7e9-441f-a55c-8541353b2872"]}
Fixed In Version: nsd-4.15.1-1.el10_4 nsd-4.15.1-1.el10_3 nsd-4.15.1-1.el9 nsd-4.15.1-1.fc43 nsd-4.15.1-1.el10_2 nsd-4.15.1-1.fc44 nsd-4.15.1-1.fc45 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-09-08 00:27:11 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: 2524301    

Description Vladimir Vasilev 2026-08-26 11:40:19 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.

The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open.

Comment 1 Fedora Update System 2026-08-28 07:31:08 UTC
FEDORA-2026-3ff003d397 (nsd-4.15.1-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-3ff003d397

Comment 2 Fedora Update System 2026-08-28 07:31:28 UTC
FEDORA-EPEL-2026-5064a05224 (nsd-4.15.1-1.el9) has been submitted as an update to Fedora EPEL 9.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-5064a05224

Comment 3 Fedora Update System 2026-08-31 17:51:11 UTC
FEDORA-2026-bf1539678e 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-bf1539678e`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-bf1539678e

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

Comment 4 Fedora Update System 2026-08-31 18:02:51 UTC
FEDORA-EPEL-2026-c16f6b76bf has been pushed to the Fedora EPEL 10.4 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-c16f6b76bf

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

Comment 5 Fedora Update System 2026-08-31 18:11:52 UTC
FEDORA-2026-3ff003d397 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-3ff003d397`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-3ff003d397

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

Comment 6 Fedora Update System 2026-08-31 18:13:53 UTC
FEDORA-EPEL-2026-b69054a78f has been pushed to the Fedora EPEL 10.3 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-b69054a78f

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

Comment 7 Fedora Update System 2026-08-31 18:23:00 UTC
FEDORA-EPEL-2026-5064a05224 has been pushed to the Fedora EPEL 9 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-5064a05224

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

Comment 8 Fedora Update System 2026-08-31 18:26:12 UTC
FEDORA-2026-c56ac69334 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-c56ac69334`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-c56ac69334

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

Comment 9 Fedora Update System 2026-08-31 18:30:34 UTC
FEDORA-EPEL-2026-4a0c7835ec has been pushed to the Fedora EPEL 10.2 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-4a0c7835ec

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

Comment 10 Fedora Update System 2026-09-08 00:27:11 UTC
FEDORA-EPEL-2026-c16f6b76bf (nsd-4.15.1-1.el10_4) has been pushed to the Fedora EPEL 10.4 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 11 Fedora Update System 2026-09-08 00:30:23 UTC
FEDORA-EPEL-2026-b69054a78f (nsd-4.15.1-1.el10_3) has been pushed to the Fedora EPEL 10.3 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 12 Fedora Update System 2026-09-08 00:44:57 UTC
FEDORA-EPEL-2026-5064a05224 (nsd-4.15.1-1.el9) has been pushed to the Fedora EPEL 9 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 13 Fedora Update System 2026-09-08 00:56:09 UTC
FEDORA-2026-3ff003d397 (nsd-4.15.1-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 14 Fedora Update System 2026-09-08 01:04:40 UTC
FEDORA-EPEL-2026-4a0c7835ec (nsd-4.15.1-1.el10_2) has been pushed to the Fedora EPEL 10.2 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 15 Fedora Update System 2026-09-08 01:11:01 UTC
FEDORA-2026-bf1539678e (nsd-4.15.1-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 16 Fedora Update System 2026-09-11 18:51:38 UTC
FEDORA-2026-c56ac69334 (nsd-4.15.1-1.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.