A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).
Weakness
The product calls free() twice on the same memory address.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Openssh-ssh1 | Ubuntu | devel | * |
| Openssh-ssh1 | Ubuntu | esm-apps/bionic | * |
| Openssh-ssh1 | Ubuntu | esm-apps/focal | * |
| Openssh-ssh1 | Ubuntu | esm-apps/jammy | * |
| Openssh-ssh1 | Ubuntu | esm-apps/noble | * |
| Openssh-ssh1 | Ubuntu | esm-apps/resolute | * |
| Openssh-ssh1 | Ubuntu | jammy | * |
| Openssh-ssh1 | Ubuntu | noble | * |
| Openssh-ssh1 | Ubuntu | questing | * |
| Openssh-ssh1 | Ubuntu | resolute | * |
| Openssh-ssh1 | Ubuntu | upstream | * |