CVE-2026-110926 PUBLISHED

Openssh: openssh: shared lz77 compression dictionary leaks plaintext across channels

Assigner: redhat
Reserved: 15.10.2026 Published: 15.10.2026 Updated: 15.10.2026

A flaw was found in OpenSSH. When compression is negotiated, channels on the same connection share one LZ77 dictionary. A peer who can write on one channel can recover plaintext from another channel by chosen-plaintext lengths.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS Score: 5.3

Product Status

Vendor Red Hat
Product Red Hat Enterprise Linux 10
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 6
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 7
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 9
Versions Default: affected
Vendor Red Hat
Product Red Hat Hardened Images
Versions Default: unaffected
Vendor Red Hat
Product Red Hat Hardened Images
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected
Vendor Red Hat
Product Red Hat OpenShift Container Platform 4
Versions Default: affected

Workarounds

Leave Compression disabled. The client default is already off. Prefer application-level compression instead of SSH compression.

Credits

  • Red Hat would like to thank Fabian Bäumer and Marcus Brinkmann for reporting this issue.

References

Problem Types

  • Observable Discrepancy CWE