CVE-2026-110926: Observable Discrepancy in Red Hat Red Hat Hardened Images

CVE-2026-110926 describes a flaw in OpenSSH where, when compression is enabled, multiple channels within the same connection share a single LZ77 compression dictionary. This shared dictionary allows an attacker who can write data on one channel to infer plaintext from another channel by exploiting chosen-plaintext length variations. The vulnerability has a CVSS 3.1 base score of 5.3, indicating a medium severity level. There are no patches or vendor advisories provided in the input data, and no known exploits in the wild have been reported.

An attacker with the ability to write on one channel of an OpenSSH connection that uses compression can potentially recover plaintext data from other channels on the same connection. This compromises confidentiality but does not affect integrity or availability. The attack requires local privileges on the connection and has a high complexity due to the need for chosen-plaintext manipulation.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, consider disabling compression in OpenSSH configurations to mitigate the risk of this vulnerability.