CVE-2026-55654
Fixed in a distro release EPSS <1%CVSS 3.7
A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.
Products: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat Hardened Images, Red Hat Update Infrastructure 5, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, 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 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 |
| Debian 13 | openssh | no fix |
| Debian 14 | openssh | 1:10.4p1-5 |
| Debian 14 | openssh-gssapi | no fix |
| 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 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 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 |
| Rocky Linux 10 | openssh | 0:9.9p1-25.el10_2.rocky.0.1 |
| 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 |