Bug 2530690

Summary:	CVE-2026-56855 opkssh: golang.org/x/crypto/ssh: Denial of Service via crafted messages [epel-all]
Product:	[Fedora] Fedora EPEL	Reporter:	jkelly <jkelly>
Component:	opkssh	Assignee:	Till Hofmann <thofmann>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	epel10	CC:	go-sig, thofmann
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["6149aca5-d0d4-472f-b5bb-730faf189259"]}
Fixed In Version:	opkssh-0.16.0-3.el10_2 opkssh-0.16.0-3.el10_3	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-09-21 00:28:32 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:	2528050

Description jkelly 2026-09-09 10:29:18 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.

Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.

Comment 1 Fedora Update System 2026-09-12 08:52:52 UTC

FEDORA-EPEL-2026-878ec4ee25 (opkssh-0.16.0-3.el10_2) has been submitted as an update to Fedora EPEL 10.2.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-878ec4ee25

Comment 2 Fedora Update System 2026-09-12 08:52:57 UTC

FEDORA-EPEL-2026-9f73888869 (opkssh-0.16.0-3.el10_3) has been submitted as an update to Fedora EPEL 10.3.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-9f73888869

Comment 3 Fedora Update System 2026-09-13 18:39:37 UTC

FEDORA-EPEL-2026-878ec4ee25 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-2026-878ec4ee25

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

Comment 4 Fedora Update System 2026-09-13 18:45:12 UTC

FEDORA-EPEL-2026-9f73888869 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-2026-9f73888869

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

Comment 5 Fedora Update System 2026-09-21 00:28:32 UTC

FEDORA-EPEL-2026-878ec4ee25 (opkssh-0.16.0-3.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 6 Fedora Update System 2026-09-21 00:42:47 UTC

FEDORA-EPEL-2026-9f73888869 (opkssh-0.16.0-3.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.