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.
| Software | From | Fixed in |
|---|---|---|
| openbsd / openssh | 9.8 | 9.8.x |
| openbsd / openssh | 9.9 | 9.9.x |
| openbsd / openssh | 9.9-p1 | 9.9-p1.x |
| openbsd / openssh | 9.5-p1 | 9.5-p1.x |
| openbsd / openssh | 9.6 | 9.6.x |
| openbsd / openssh | 9.6-p1 | 9.6-p1.x |
| openbsd / openssh | 9.7 | 9.7.x |
| openbsd / openssh | 9.7-p1 | 9.7-p1.x |
| openbsd / openssh | 9.8-p1 | 9.8-p1.x |
| canonical / ubuntu_linux | 24.04 | 24.04.x |
| canonical / ubuntu_linux | 24.10 | 24.10.x |
| debian / debian_linux | 11.0 | 11.0.x |
| debian / debian_linux | 12.0 | 12.0.x |
| debian / debian_linux | 13.0 | 13.0.x |
- http://seclists.org/fulldisclosure/2025/Feb/18
- http://seclists.org/fulldisclosure/2025/May/7
- http://seclists.org/fulldisclosure/2025/May/8
- https://access.redhat.com/security/cve/CVE-2025-26466
- https://bugzilla.redhat.com/show_bug.cgi?id=2345043
- https://bugzilla.suse.com/show_bug.cgi?id=1237041
- https://seclists.org/oss-sec/2025/q1/144
- https://security-tracker.debian.org/tracker/CVE-2025-26466
- https://security.netapp.com/advisory/ntap-20250228-0002/
- https://ubuntu.com/security/CVE-2025-26466
- https://www.openwall.com/lists/oss-security/2025/02/18/1
- https://www.openwall.com/lists/oss-security/2025/02/18/4
- https://www.qualys.com/2025/02/18/openssh-mitm-dos.txt
Deep Security Visibility Without the Complexity
SynScan provides clear, real-time security insights so you can monitor your attack surface, spot risks early, and act fast—without extra complexity.
- No setup fees
- 5-min deployment
- Cancel anytime