CVE-2026-59848 Red Hat CVE debrief

Who should care

Users of libssh clients, system administrators, security teams, and operators managing systems that utilize libssh should be aware of this vulnerability and take steps to mitigate it. Reviewing and updating libssh to the latest version is recommended. Affected parties should also consider implementing compensating controls and monitoring client logs for suspicious activity.

Technical summary

The libssh library has a flaw that allows a malicious SFTP server to send responses for unknown request IDs, which libssh clients keep queued indefinitely. This causes unbounded memory growth and client-side denial of service. The issue is related to the handling of SFTP requests and responses in libssh clients. Affected systems should review their libssh client deployments and consider mitigation strategies to prevent potential denial-of-service conditions.

Defensive priority

Medium priority

Recommended defensive actions

• Update libssh to the latest version
• Implement compensating controls to limit the impact of a potential attack
• Monitor libssh client logs for suspicious activity
• Review libssh client deployments for exposure
• Perform vulnerability management and asset inventory for affected systems
• Track exceptions and retest remediated assets
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-21T14:16:34.790Z and was last modified on 2026-07-22T20:17:04.123Z. The NVD entry is currently Undergoing Analysis. This information is based on the provided source corpus. Further verification is recommended to confirm affected scope and vendor guidance. The libssh library's handling of SFTP requests and responses is a key area of focus for mitigation.

Official resources