CVE-2026-59847 Red Hat CVE debrief

Who should care

Users of libssh with OpenSSL backend, operators of affected systems, platform administrators, vulnerability management teams, and security teams should be aware of this vulnerability. They need to assess their exposure, plan for updates or mitigations, and monitor for suspicious activity. Affected deployments need to be identified and prioritized for remediation.

Technical summary

The vulnerability is caused by incorrect AES-GCM finalization checks in libssh builds that use the OpenSSL backend. This can allow an in-path attacker to modify plaintext on the wire without detection, effectively removing integrity protection. The affected context is libssh with OpenSSL backend. Defensive impact includes potential data integrity risks. Source-grounded technical framing emphasizes cryptographic weaknesses and potential operational impacts.

Defensive priority

Medium priority due to potential for data tampering and operational impact

Recommended defensive actions

• Apply patches or updates from the vendor
• Use compensating controls such as data integrity checks
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

Evidence is limited, further verification needed. The vulnerability details are based on the CVE record and NVD information. Affected systems and deployments need to be identified for thorough review. Additional verification tasks include checking for OpenSSL backend usage in libssh builds and assessing potential data tampering risks.

Official resources