Threats affecting pkg:deb/debian/openssh

CVE-2026-35386 is a low-severity vulnerability in OpenSSH versions before 10.3 where command execution can occur due to improper handling of shell metacharacters in usernames on the command line. Exploitation requires an untrusted username input and non-default ssh_config settings involving the % character. The vulnerability has a CVSS score of 3.6 and does not have known exploits in the wild. No official patch or remediation details are provided in the available data.

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.

OpenSSH versions from 8.9 up to but not including 9.3 have a vulnerability in ssh-add where smartcard keys are added to ssh-agent without enforcing the intended per-hop destination constraints. This could potentially allow keys to be used in unintended contexts. The issue is fixed in OpenSSH version 9.3.