Bug 2503675

Summary: CVE-2026-59850 libssh: libssh: use-after-free via data callbacks on closed channels [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: libsshAssignee: Andreas Schneider <asn>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: ansasaki, asn, jjelen, negativo17, shebburn
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---Flags: fedora-admin-xmlrpc: mirror+
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["cf52b3f0-2673-4b56-9831-c5683d97a998"]}
Fixed In Version: libssh-0.11.5-1.fc43 libssh-0.12.1-1.fc44 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-07-23 01:03:40 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: 2498183    

Description Vladimir Vasilev 2026-07-21 15:16:32 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 was found in libssh channel data handling. In channel_rcv_data() in src/channels.c, incoming channel DATA messages could still be processed after the channel had already been marked as remotely closed. In SFTP-backed applications and other callback-driven consumers, this creates a path where data callbacks may observe channel-associated state after it has already been torn down or freed, leading to crashes and possible use-after-free conditions.

Comment 1 Fedora Update System 2026-07-22 09:32:55 UTC
FEDORA-2026-0e46c91ccf (libssh-0.12.1-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-0e46c91ccf

Comment 2 Fedora Update System 2026-07-22 09:33:53 UTC
FEDORA-2026-063caa9112 (libssh-0.11.5-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-063caa9112

Comment 3 Fedora Update System 2026-07-23 01:03:40 UTC
FEDORA-2026-063caa9112 (libssh-0.11.5-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 4 Fedora Update System 2026-07-23 01:20:31 UTC
FEDORA-2026-0e46c91ccf (libssh-0.12.1-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.