Bug 2498183 (CVE-2026-59850)

Summary: CVE-2026-59850 libssh: libssh: use-after-free via data callbacks on closed channels
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libssh. If data packets are processed after a channel is closed, channel data callbacks can be invoked after the associated data has already been freed, leading to crashes or possible use-after-free conditions.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2503675    
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Description OSIDB Bzimport 2026-07-08 18:22:50 UTC 
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 2 errata-xmlrpc 2026-08-17 20:53:19 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:55855 https://access.redhat.com/errata/RHSA-2026:55855