🛡️ CVE-2025-26466 — debian-linux

🟡 CVSS 5.9 — Medium ✅ No Known Exploit CWE-770 NVD
5.9
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2025-26466 is classified as CWE-770: Allocation of Resources Without Limits. Resources are allocated on request with no cap, so a client can exhaust them.

Affected software

CVE-2025-26466 is recorded against 3 packages.

  • debian-linux
  • openssh
  • ubuntu-linux

Timeline and source

Published on 28 February 2025 and last revised on 30 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

access.redhat.com
bugzilla.redhat.com
seclists.org
www.qualys.com
seclists.org
seclists.org
seclists.org
bugzilla.suse.com
security-tracker.debian.org
security.netapp.com
ubuntu.com
www.openwall.com
www.openwall.com
www.vicarius.io
www.vicarius.io

CVE-2025-26466 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 5.9
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-770
Public Exploit ✅ No
Source NVD
Published 2025-02-28
Updated 2026-08-11
Modified 2026-06-30
Fix URL N/A

Affected Packages

Software From version Fixed in
debian-linux
openssh
ubuntu-linux

References

Similar Threats

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