CVE-2025-26466
Openssh: denial-of-service in openssh
MEDIUM 5.9EPSS 40.6%
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.
- Affected
- Red Hat · OpenSSH · Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 9
- CVSS v3.1 NVD
- 5.9 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 40.65% chance of exploitation in the next 30 days, 99th percentile
- Published
- 2025-02-28
- Updated
- 2026-10-15
Proof-of-concept exploits (5)
- mrowkoob/CVE-2025-26466-msf1★ · 2025-06-23
- rxerium/CVE-2025-264665★ · 2025-10-14
- acidboonrs/cve-2025-26466-openssh-poc0★ · 2026-07-29
- tpirate/CVE-2025-264660★ · 2026-04-02
- K0n9-log/cve-2025-26466-canvas0★ · 2026-10-09
Security advisories
- https://access.redhat.com/security/cve/CVE-2025-26466
- https://bugzilla.suse.com/show_bug.cgi?id=1237041
- 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
- https://bugzilla.redhat.com/show_bug.cgi?id=2345043