Explore top 10 tips to secure your open-source projects now. Read More

×
Alerts This Week
Warning Icon 1 579
Alerts This Week
Warning Icon 1 579

Fedora 43 OpenSSH Important Fixes for Client-Side DoS CVE-2026-55653

fedora
Calendar Grey July 10, 2026
Dist Fedora Esm H88
Enhance your system's security with this important Fedora Advisory on OpenSSH addressing multiple potential issues.
CVE-2026-55653: Fix double free in openssh DH-GEX client path during FIPS known- group validation that leads to client-side denial of service CVE-2026-55654: Fix heap out-of-bounds...

Summary

SSH (Secure SHell) is a program for logging into and executing

commands on a remote machine. SSH is intended to replace rlogin and

rsh, and to provide secure encrypted communications between two

untrusted hosts over an insecure network. X11 connections and

arbitrary TCP/IP ports can also be forwarded over the secure channel.

OpenSSH is OpenBSD's version of the last free version of SSH, bringing

it up to date in terms of security and features.

This package includes the core files necessary for both the OpenSSH

client and server. To make this package useful, you should also

install openssh-clients, openssh-server, or both.

Update Information:

CVE-2026-55653: Fix double free in openssh DH-GEX client path during FIPS known- group validation that leads to client-side denial of service CVE-2026-55654: Fix heap out-of-bounds read during GSSAPI indicator cleanup due to missing NULL terminator CVE-2026-55655: Fix MITM of X11 forwarding via abstract UNIX socket pre-binding

Topics%20covered

Topics Covered

security advisory fedora important openssh x11 forwarding client-side denial of service

Change Log

* Tue Jul 7 2026 Zoltan Fridrich - 10.0p1-10 - CVE-2026-55653: Fix double free in openssh DH-GEX client path during FIPS known-group validation that leads to client-side denial of service - CVE-2026-55654: Fix heap out-of-bounds read during GSSAPI indicator cleanup due to missing NULL terminator - CVE-2026-55655: Fix MITM of X11 forwarding via abstract UNIX socket pre-binding

References


[ 1 ] Bug #2442505 - 0043-openssh-8.7p1-ssh-manpage.patch introduces duplicates in documentation https://bugzilla.redhat.com/show_bug.cgi?id=2442505

Update Instructions

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-95b955a09b' at the command line. For more information, refer to the dnf documentation available at http://dnf.readthedocs.io/en/latest/command_ref.html#upgrade-command-label

Severity
important
Lowest
Low
Medium
High
Critical

Name: openssh
Product: Fedora 43
Version: 10.0p1
Release: 10.fc43
URL: http://www.openssh.com/portable.html
Summary: An open source implementation of SSH protocol version 2

Topics%20covered

Topics Covered

security advisory fedora important openssh x11 forwarding client-side denial of service

Get the latest News and Insights

Get the latest Linux and open source security news straight to your inbox.