CVE-2025-26466

A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack.

• CWE-770
• CWE-770

• https://access.redhat.com/security/cve/CVE-2025-26466Third Party Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=2345043Issue Tracking
• https://seclists.org/oss-sec/2025/q1/144
• https://www.qualys.com/2025/02/18/openssh-mitm-dos.txtThird Party Advisory
• http://seclists.org/fulldisclosure/2025/Feb/18
• http://seclists.org/fulldisclosure/2025/May/7
• http://seclists.org/fulldisclosure/2025/May/8
• https://bugzilla.suse.com/show_bug.cgi?id=1237041Third Party Advisory
• https://security-tracker.debian.org/tracker/CVE-2025-26466Third Party Advisory
• https://security.netapp.com/advisory/ntap-20250228-0002/Third Party Advisory
• https://ubuntu.com/security/CVE-2025-26466Third Party Advisory
• https://www.openwall.com/lists/oss-security/2025/02/18/1Mailing List, Third Party Advisory
• https://www.openwall.com/lists/oss-security/2025/02/18/4Mailing List, Third Party Advisory
• https://www.vicarius.io/vsociety/posts/cve-2025-26466-detection-script-memory-consumption-vulnerability-in-openssh
• https://www.vicarius.io/vsociety/posts/cve-2025-26466-mitigation-script-memory-consumption-vulnerability-in-openssh
• https://www.qualys.com/2025/02/18/openssh-mitm-dos.txtThird Party Advisory

Published

Feb 28, 2025

Last Modified

Jun 25, 2026

Status

Modified