Medium · published March 1, 2025
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.
| Product | Versions | Fixed in |
|---|---|---|
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| openbsd/openssh | all versions | — |
| canonical/ubuntu_linux | all versions | — |
| canonical/ubuntu_linux | all versions | — |
| debian/debian_linux | all versions | — |
| debian/debian_linux | all versions | — |
| debian/debian_linux | all versions | — |