A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating "secret_hash" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.
CVSS Score
6.5
EPSS Score
0.047
Published
2021-08-31
libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.
CVSS Score
5.9
EPSS Score
0.041
Published
2020-07-29
A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.
CVSS Score
5.3
EPSS Score
0.031
Published
2020-04-13
A flaw was found with the libssh API function ssh_scp_new() in versions before 0.9.3 and before 0.8.8. When the libssh SCP client connects to a server, the scp command, which includes a user-provided path, is executed on the server-side. In case the library is used in a way where users can influence the third parameter of the function, it would become possible for an attacker to inject arbitrary commands, leading to a compromise of the remote target.
CVSS Score
7.1
EPSS Score
0.032
Published
2019-12-10
A vulnerability was found in libssh's server-side state machine before versions 0.7.6 and 0.8.4. A malicious client could create channels without first performing authentication, resulting in unauthorized access.
CVSS Score
9.1
EPSS Score
0.918
Published
2018-10-17
libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key exchange methods to 128 bits, which makes it easier for man-in-the-middle attackers to decrypt or intercept SSH sessions via unspecified vectors, aka a "bits/bytes confusion bug."
CVSS Score
5.9
EPSS Score
0.024
Published
2016-04-13
The (1) SSH_MSG_NEWKEYS and (2) SSH_MSG_KEXDH_REPLY packet handlers in package_cb.c in libssh before 0.6.5 do not properly validate state, which allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a crafted SSH packet.
CVSS Score
7.5
EPSS Score
0.039
Published
2016-04-13
Double free vulnerability in the ssh_packet_kexinit function in kex.c in libssh 0.5.x and 0.6.x before 0.6.4 allows remote attackers to cause a denial of service via a crafted kexinit packet.
CVSS Score
5.0
EPSS Score
0.051
Published
2014-12-29
The RAND_bytes function in libssh before 0.6.3, when forking is enabled, does not properly reset the state of the OpenSSL pseudo-random number generator (PRNG), which causes the state to be shared between children processes and allows local users to obtain sensitive information by leveraging a pid collision.
CVSS Score
1.9
EPSS Score
0.004
Published
2014-03-14
The publickey_from_privatekey function in libssh before 0.5.4, when no algorithm is matched during negotiations, allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a "Client: Diffie-Hellman Key Exchange Init" packet.
CVSS Score
4.3
EPSS Score
0.03
Published
2013-02-05