Bug 2553281

Summary:	CVE-2026-39834 vhs: golang.org/x/crypto/ssh: Denial of Service due to integer overflow in SSH channel write [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Avinash Hanwate <ahanwate>
Component:	vhs	Assignee:	Carl George 🤠 <carlwgeorge>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	carlwgeorge, go-sig
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["2d749e5e-fe0a-4fae-8339-549023987a9d"]}
Fixed In Version:	vhs-0.12.1-1.fc45 vhs-0.11.0-4.fc44	Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2026-11-01 03:35:22 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:	2480676

Description Avinash Hanwate 2026-10-15 10:22:19 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.

When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.

Comment 1 Fedora Update System 2026-10-23 23:47:33 UTC

FEDORA-2026-ff352aea5d (vhs-0.12.1-1.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ff352aea5d

Comment 2 Fedora Update System 2026-10-24 00:07:34 UTC

FEDORA-2026-ba39729bff (vhs-0.11.0-4.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ba39729bff

Comment 3 Fedora Update System 2026-10-24 17:26:44 UTC

FEDORA-2026-ba39729bff 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-ba39729bff`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-ba39729bff

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

Comment 4 Fedora Update System 2026-10-24 18:16:59 UTC

FEDORA-2026-ff352aea5d 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-ff352aea5d`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-ff352aea5d

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

Comment 5 Fedora Update System 2026-11-01 03:35:22 UTC

FEDORA-2026-ff352aea5d (vhs-0.12.1-1.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 6 Fedora Update System 2026-11-01 03:36:09 UTC

FEDORA-2026-ba39729bff (vhs-0.11.0-4.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.