CVE-2026-55655
Fixed in a distro release EPSS <1%CVSS 5.0
A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.
Products: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions, Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions, Red Hat Enterprise Linux 9.6 Extended Update Support, Red Hat Hardened Images, Red Hat OpenShift AI 3.0, Red Hat OpenShift AI 3.2, Red Hat OpenShift AI 3.3, Red Hat OpenShift AI 3.4, Red Hat OpenShift AI 3.5, Red Hat Update Infrastructure 5, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | openssh | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 10 | openssh-askpass | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 10 | openssh-clients | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 10 | openssh-keycat | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 10 | openssh-keysign | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 10 | openssh-server | 9.9p1-25.el10_2.alma.1 |
| AlmaLinux 8 | openssh | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-askpass | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-cavs | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-clients | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-keycat | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-ldap | 8.0p1-30.el8_10 |
| AlmaLinux 8 | openssh-server | 8.0p1-30.el8_10 |
| AlmaLinux 8 | pam_ssh_agent_auth | 0.10.3-7.30.el8_10 |
| AlmaLinux 9 | openssh | 9.9p1-9.el9_8.alma.1 |
| AlmaLinux 9 | openssh-askpass | 9.9p1-9.el9_8.alma.1 |
| AlmaLinux 9 | openssh-clients | 9.9p1-9.el9_8.alma.1 |
| AlmaLinux 9 | openssh-keycat | 9.9p1-9.el9_8.alma.1 |
| AlmaLinux 9 | openssh-server | 9.9p1-9.el9_8.alma.1 |
| AlmaLinux 9 | pam_ssh_agent_auth | 0.10.4-7.9.el9_8.alma.1 |
| Amazon Linux 2023 | openssh | 9.9p1-10.amzn2023.0.1 |
| Amazon Linux 2023 | openssh-clients | 9.9p1-10.amzn2023.0.1 |
| Amazon Linux 2023 | openssh-keycat | 9.9p1-10.amzn2023.0.1 |
| Amazon Linux 2023 | openssh-server | 9.9p1-10.amzn2023.0.1 |
| Amazon Linux 2023 | openssh-sk-dummy | 9.9p1-10.amzn2023.0.1 |
| Amazon Linux 2023 | pam_ssh_agent_auth | 0.10.4-9.10.amzn2023.0.1 |
| Red Hat Enterprise Linux 10.2 | openssh | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-askpass | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-askpass-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-clients | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-clients-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-debugsource | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-keycat | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-keycat-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-keysign | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-keysign-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-server | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-server-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 10.2 | openssh-sk-dummy-debuginfo | 0:9.9p1-25.el10_2 |
| Red Hat Enterprise Linux 8 | openssh | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-askpass | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-askpass-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-cavs | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-cavs-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-clients | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-clients-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-debugsource | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-keycat | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-keycat-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-ldap | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-ldap-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-server | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | openssh-server-debuginfo | 0:8.0p1-30.el8_10 |
| Red Hat Enterprise Linux 8 | pam_ssh_agent_auth | 0:0.10.3-7.30.el8_10 |
| Red Hat Enterprise Linux 8 | pam_ssh_agent_auth-debuginfo | 0:0.10.3-7.30.el8_10 |
| Red Hat Enterprise Linux 9 | openssh | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-askpass | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-askpass-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-clients | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-clients-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-debugsource | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-keycat | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-keycat-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-server | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-server-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | openssh-sk-dummy-debuginfo | 0:9.9p1-9.el9_8 |
| Red Hat Enterprise Linux 9 | pam_ssh_agent_auth | 0:0.10.4-7.9.el9_8 |
| Red Hat Enterprise Linux 9 | pam_ssh_agent_auth-debuginfo | 0:0.10.4-7.9.el9_8 |
| Red Hat Enterprise Linux eus 10.0 | openssh | 0:9.9p1-7.el10_0.5 |
| Red Hat Enterprise Linux eus 10.0 | openssh-askpass | 0:9.9p1-7.el10_0.5 |
| Red Hat Enterprise Linux eus 10.0 | openssh-clients | 0:9.9p1-7.el10_0.5 |
| Red Hat Enterprise Linux eus 10.0 | openssh-keycat | 0:9.9p1-7.el10_0.5 |
| Red Hat Enterprise Linux eus 10.0 | openssh-keysign | 0:9.9p1-7.el10_0.5 |
| Red Hat Enterprise Linux eus 10.0 | openssh-server | 0:9.9p1-7.el10_0.5 |
| Red Hat hummingbird 1 | openssh | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-askpass | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-clients | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-keycat | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-keysign | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-server | 0:10.3p1-6.hum1 |
| Red Hat hummingbird 1 | openssh-sk-dummy | 0:10.3p1-6.hum1 |
| Red Hat rhel e4s 9.4 | openssh-clients | 0:8.7p1-38.el9_4.10 |
| Red Hat rhel e4s 9.4 | openssh-server | 0:8.7p1-38.el9_4.10 |
| Red Hat rhel eus 9.6 | openssh | 0:8.7p1-45.el9_6.5 |
| Red Hat rhel eus 9.6 | openssh-askpass | 0:8.7p1-45.el9_6.5 |
| Red Hat rhel eus 9.6 | openssh-clients | 0:8.7p1-45.el9_6.5 |
| Red Hat rhel eus 9.6 | openssh-keycat | 0:8.7p1-45.el9_6.5 |
| Red Hat rhel eus 9.6 | openssh-server | 0:8.7p1-45.el9_6.5 |
| Red Hat rhel eus 9.6 | pam_ssh_agent_auth | 0:0.10.4-5.45.el9_6.5 |
| Rocky Linux 10 | openssh | 0:9.9p1-25.el10_2.rocky.0.1 |
| Rocky Linux 8 | openssh | 0:8.0p1-30.el8_10 |
| Rocky Linux 9 | openssh | 0:9.9p1-9.el9_8.rocky.0.1 |
| Ubuntu 18.04 LTS | openssh-ssh1 | no fix |
| Ubuntu 20.04 LTS | openssh-ssh1 | no fix |
| Ubuntu 22.04 LTS | openssh-ssh1 | no fix |
| Ubuntu 24.04 LTS | openssh-ssh1 | no fix |
| Ubuntu 25.10 | openssh | no fix |
| Ubuntu 25.10 | openssh-ssh1 | no fix |
| Ubuntu 26.04 LTS | openssh-ssh1 | no fix |
| Ubuntu 26.10 | openssh-ssh1 | no fix |