A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The exploit has been publicly disclosed and may be utilized. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch.

A flaw was found in Dropbear. When running in multi-user mode and authenticating users, the dropbear ssh server does the socket forwardings requested by the remote client as root, only switching to the logged-in user upon spawning a shell or performing some operations like reading the user's files. With the recent ability of also using unix domain sockets as the forwarding destination any user able to log in via ssh can connect to any unix socket with the root's credentials, bypassing both file system restrictions and any SO_PEERCRED / SO_PASSCRED checks performed by the peer.